JP2020073295A - Cut diamond and manufacturing method thereof - Google Patents

Abstract

To provide a diamond having a round cut in a manner that a light entered into the diamond from a crown, especially a table facet is reflected totally in the pavilion and also emitted from a girdle part, hence linear lights can be observed or linear dark areas can be observed, and a cut method thereof.SOLUTION: The round cut diamond has a girdle constituted of girdle facets tilted 0.1 degree or over and 45 degree or under to the outside of the crown toward the central axis going from the table facet center to the curette surface center (however, limited to an angle smaller than the angle that the crown surface makes with the central axis), wherein the girdle facet is characterized by that total reflection of a light flux entered from the table facet and reflected at the pavilion side facet (i.e., re-reflecting to the inside of the diamond) is reduced by the girdle, and outgoing beam from the girdle is increased.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a method for producing a cut diamond that is a cut diamond and a cut diamond.

  In the conventional cut diamond, the girdle at the boundary between the crown and the pavilion is cut parallel to the normal direction of the table facet, that is, when the diamond is erected upright, it becomes a vertical surface. This is an indispensable structure because it is necessary to firmly fix the diamond at the time of cutting the diamond. However, the girdle surface processed in this way is optically inefficient, and the light from the table facet, which is the main inlet of the light emitted by the diamond, cannot be effectively used.

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  Light that enters the diamond from the crown, especially the table facets, is totally reflected by the pavilion and is also emitted from the girdle part, so that a linear light can be observed, or a round cut that makes it possible to observe a dark line area is performed. There has been a demand for a diamond and a method for cutting the diamond.

  In order to solve such a problem, the present invention provides, as a first invention, the girdle outside the crown with respect to the central axis passing from the center of the table facet to the center of the curette surface at 0.1 degrees or more and 45 degrees ( However, the crown surface is limited to an angle smaller than the angle formed by the central axis). ) Is reduced by a girdle, and a round-cut diamond having a girdle facet with more emitted light from the girdle is provided.

  Next, as a second invention, the girdle is 0.1 degrees or more and 45 degrees inside the crown with respect to the center axis passing through the center of the curette surface from the center of the table facet (however, the angle formed by the pavilion surface and the center axis). The present invention provides a round-cut diamond having girdle facets configured by girdle facets inclined below, and having the girdle increase the total reflection of the luminous flux incident from the table facets and reflected by the facets on the pavilion side.

  Next, as a third invention, the width of the girdle facet is 0.2% or more and 10% or less with respect to the height between the curette surface and the table facet. Offering round diamonds.

  Next, as a fourth invention, each facet except the table facet of the crown is arranged point-symmetrically with respect to the central axis in front view of the table facet, and each facet except the curette of the pavilion has the central axis. The round-cut diamond according to any one of the first invention to the third invention, which is arranged in point symmetry with respect to.

  Next, as a fifth invention, the table facet is a hexagon, the number of facets constituting the crown excluding the girdle facet is 54 faces excluding the table facet, and the number of facets constituting the pavilion is the above. Round cuts according to any one of the first to fourth inventions, except for the girdle facets, the curettes are 32 faces without counting, and the total number of facets is 88 faces including the table facets and the girdle facets. Offer a diamond.

  Next, as a sixth invention, the table facet is a hexagon, the number of facets constituting the crown excluding the girdle facet is 36 faces excluding the table facet, and the number of facets constituting the pavilion is the above. The round-cut diamond according to any one of the first to fourth inventions, in which the number of facets, excluding girdle facets, is 25 with the culet as a face, and the total number of facets is 63 faces including table facets and girdle facets. I will provide a.

  Next, as a seventh invention, the girdle is 0.1 degrees or more and 45 degrees outside the crown with respect to the central axis passing from the center of the table facet to the center of the curette surface (however, the angle formed by the crown surface with the central axis). Designed with rough diamonds or other cuts that consist of girdle facets that are inclined below, and reduce the total reflection of the light beam that enters from the table facet and is reflected by the facets on the pavilion side with the girdle. Provide a method for manufacturing a round-cut diamond for grinding and forming the formed diamond.

  Next, as an eighth invention, the girdle is 0.1 degrees or more and 45 degrees inward from the crown with respect to the center axis passing through the center of the curette surface from the center of the table facet (however, the angle formed by the pavilion surface and the center axis). Designed with rough diamonds or other cuts with girdles that increase the total reflection of the light flux that is incident from the table facet and reflected by the facets on the pavilion side Provide a method for manufacturing a round-cut diamond for grinding and forming the formed diamond.

  Next, as a ninth invention, the girdle facet is designed with a rough diamond or other cut so that the width is 0.2% or more and 10% or less with respect to the height between the curette surface and the table facet. A method of manufacturing a round-cut diamond according to the seventh invention or the eighth invention, in which the formed diamond is formed by grinding.

  Next, as a tenth invention, each facet except the table facet of the crown is designed by rough diamond or other cut so as to be arranged asymmetrically with respect to the center axis in front view of the table facet. Provided is a method for producing a round-cut diamond according to the seventh invention or the ninth invention, in which the diamond is formed by grinding.

  Next, as an eleventh invention, the table facet is a hexagon, the number of facets constituting the crown excluding the girdle facet is 54 faces excluding the table facet, and the number of facets constituting the pavilion is Except for the girdle facets, there are 32 faces, not counting the culet, and the total number of facets is 88 face faces including the table facets and girdle facets. A method for manufacturing a round-cut diamond according to any one of the seventh to tenth inventions is provided.

  Next, as a twelfth invention, the table facet is a hexagon, the number of facets forming the crown excluding the girdle facet is 36 faces excluding the table facet, and the number of facets forming the pavilion is Excluding the girdle facets, the curette has 25 faces, and the total number of facets is 63 facets including the table facets and the girdle facets. The method for manufacturing a round-cut diamond according to any one of the seventh invention to the tenth invention.

  The girdle surface of the diamond provided by the present invention is not parallel to the central axis but is cut at an angle, so that more light internally reflected by the pavilion can be emitted than conventional diamond. It becomes possible, or it becomes possible to emit less light that is internally reflected in the pavilion than in conventional diamond, so that it is possible to use peripheral facets, especially the pavilion facet in the former configuration and the crown facet in the latter configuration. It has become possible to make the difference in brightness clear and enjoy the unprecedented circular line-shaped brilliance. In addition, by limiting the angle of the girdle surface, the stone can be mechanically held when cutting the diamond, and can be fixed with nails when it is placed on a decoration such as a ring, and it is hard to scratch and shine Can be contributed.

Diagram showing the ideal diamond cut structure with 58 cuts Diagram showing the inclination of the girdle facet with respect to the center axis in the normal direction on the table facet Diagram showing fluctuation of the amount of light taken in according to the inclination of the facet with respect to the central axis in the normal direction to the table facet Diagram showing the relationship between light reflection and total reflection Conceptual diagram showing reflection inside a diamond Diagram showing the relationship between the incident angle of the incident light on the pavilion side facet and the girdle facet when the girdle facet has no inclination. Diagram showing the relationship between the incident angle of incident light on the pavilion side facet and the girdle facet when the girdle facet has an inclination outside the bottom edge of the crown Diagram showing the relationship between the incident angle of incident light on the pavilion side facet and the girdle facet when the girdle facet has a slope inward from the bottom edge of the crown Example of reflected light from the crown side facet when the table facet is point symmetric Example of reflected light from the crown side facet when the table facet is asymmetric Diagram showing ideal diamond cut configuration with 88 faces The figure which reproduces the experimental result photograph which shows the reflection aspect of the diamond which 88 planes are cut The figure which reproduced the experimental result photograph which shows the reflection mode of the diamond with which 58 sides were cut Diagram showing ideal diamond cut configuration with 63 faces The figure which reproduced the experimental result photograph which shows the reflection mode of the diamond with which 63 sides were cut A table showing the results of a questionnaire in which the apparent strengths of the brilliance of the conventional cut diamond and those of the cut diamonds of the fifth and sixth embodiments are compared. A table showing the results of a questionnaire in which the appearance preference of the conventional cut diamond and the design of the cut diamonds of the fifth and sixth embodiments are compared.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the first embodiment is defined in claims 1 and 1, the second embodiment is defined in claim 2, the third embodiment is defined in claim 3, the fourth embodiment is defined in claim 4, and the fifth embodiment is defined in claim 4. Item 5, Embodiment 6 is Claim 6, Embodiment 7 is Claim 7, Embodiment 8 is Claim 8, Embodiment 9 is Claim 9, and Embodiment 10 is Claim 10. The eleventh form corresponds to claim 11 and the twelfth embodiment corresponds to claim 12. The contents of the present invention are not limited to the following examples, and various changes can be made without departing from the scope of the present invention.

<Embodiment 1>
<Embodiment 1 of the invention>
According to the invention of the present embodiment, the girdle is 0.1 degrees or more and 45 degrees outside the crown with respect to the center axis passing through the center of the curette surface from the center of the table facet (however, the angle formed by the crown surface and the center axis is more than It is a round cut diamond having girdle facets in which the girdle reduces the total reflection of the luminous flux incident from the table facet and reflected by the facet on the pavilion side.

<Embodiment 1 of the invention>
As shown in FIG. 1, a facet of a round-cut diamond according to the present embodiment (referred to as a observable plane of a diamond created by grinding a rough stone in the past, is referred to as a observable surface of a diamond in the present application. , A curved surface represented by a girdle facet is also included.) A region above the girdle including the table facet (0101), which is the largest surface, is called a crown (0102), and a region below the girdle is called a pavilion (0103).
The light emitting surface of the diamond of the present invention has a table facet on the crown, a crown side facet (0104) other than the table facet on the crown, and a girdle facet (0105), which is not conventionally used as a light emitting surface, on the pavilion side. Then, there is a curette at the bottom (only when chamfered. It may be chamfered or not) (0106) and a pavilion side facet (0107) excluding the curette. The feature of the round-cut diamond in the present embodiment is that the girdle is 0.1 degrees or more and 45 degrees (however, outside the lowermost edge (0108) of the crown with respect to the center axis passing through the center of the table facet and the center of the curette surface (however, (Limited to an angle smaller than the angle formed by the central axis of the crown surface)) A girdle facet that is composed of inclined girdle facets and reduces the total reflection of the light beam incident from the table facet and reflected by the pavilion side facet with the girdle Have.

  "Round cut" is a typical cutting of diamond, the outline of the cut diamond is circular when viewed from above, and when viewed from the side, the trapezoid of the crown rides on the inverted triangle of the pavilion, It refers to cutting in which many planes are cut out. The most common type of round cut is the round brilliant cut. The present invention is round cut, and basically the line connecting the center point of the table facet and the center point of the curette is a line parallel to the normal line of the table facet.

  FIG. 2 shows how to measure the inclination of the girdle facet with respect to the central axis. FIG. 2a shows the inclination (θ1) of the girdle facet with respect to a straight line (C′-C ′) parallel to the central axis (C-C) when the girdle facet is protruding from the crown. θ1 is an angle in the range of 0 ° to 90 ° outside the lowermost edge of the crown with respect to the center axis, and is 0.1 ° or more and 30 ° or less in the present embodiment.

  Assuming that the scattered light is uniformly incident on any of the facets on the crown side of the diamond (this assumption is approximately correct in the general wearing condition of the diamond), the light emitted from any facet of the diamond is uniform. It is emitted as scattered light. This is because when the diamond is worn on the ring, the pavilion side is the metal ring that makes up the ring, and the incident light is relatively small or biased because it is the skin side of the finger, but the crown This is because there are not so many light-shielding devices on the side in general, so it is considered that light is uniformly incident. Light incident on the crown side is reflected on the pavilion side, so the light emitted from the facet on the crown side is represented by the direction normal to the center of gravity of that facet (the line with the highest brightness during observation: Light "). The crown side facet with the most incident light is the table facet.

  As shown in FIG. 3, the light intake amount increases as the facet inclination approaches 90 degrees with respect to the central axis (that is, closer to parallel to the table facet). This is based on the assumption that sunlight is generally evenly emitted from the overhead, or that lighting equipment is generally placed overhead in the room. That is, the luminous flux density of the luminous flux incident on the diamond is generally considered to be maximum in the central axis direction. With respect to the 0-degree axis, the region on the right side shows the case where the girdle facet protrudes outward from the lowermost edge of the crown. The amount of light taken in when the girdle facet projects outward from the lowermost edge of the crown increases or decreases in accordance with the change from 0 degree to 90 degrees to the right as shown in FIG.

As shown in FIG. 4, when light joins an optically dense medium 2 having a large refractive index n _{2 to} an optically sparse medium 1 having a small refractive index n ₁ , the angle of refraction is greater than the incident angle i. Since r is larger, the refraction angle may be 90 ° for a certain value of the incident angle. If the incident angle at this time is i ₀ , the law of refraction
n · sin θ = A (constant value)
Than,
n ₂ sini ₀ = n ₁ sin 90 °
The relationship with
Therefore,
sini ₀ = n ₁ / n ₂
It can be expressed as.
When the medium 1 is a vacuum,
sini ₀ = 1 / n ₂
Becomes
When the angle of incidence is greater than i _0, there are no refracted rays and only reflected rays. This phenomenon is called “total reflection”, and the incident angle i ₀ that causes total reflection is called the “critical angle” of the medium 2 with respect to the medium 1.

  In diamond, the optically sparse medium 1 is air, and the optically dense medium 2 is diamond. Therefore, when light is taken from the air into the diamond, total reflection does not decrease, but it is possible to cause total reflection when the light is emitted from inside the diamond into the air. .. Although it cannot be realized in reality, when a diamond is evaluated, it may be evaluated with reference to a diamond that is ideally cut. The reflection characteristics of this ideally cut diamond are such that the light incident from the crown side including the table facets is not emitted from the pavilion side, so that total reflection is repeated inside the pavilion (or only once). However, it is assumed that all the captured light is emitted from the crown side. That is, no matter what angle the light is taken in from the crown side, the angle of incidence on the surface of the pavilion is larger than the critical angle of diamond with respect to air. That is to configure the facet tilt.

  The critical angle of diamond is 24.4 °, and the incident angle when the light taken into the diamond from the crown side and the girdle facet (region indicated by g in FIG. 5) is reflected by any facet of the pavilion is 24. Total reflection occurs when the angle is less than 0.4 °. FIG. 5 is a conceptual diagram of reflection inside a diamond. θa, θb, θc, and θd are all incident angles of the light taken in from the crown side with respect to the facet of the pavilion. Since θa, θb, and θc are all obtuse angles than the critical angle 24.4 ° of diamond with respect to air, total reflection occurs. The angle of reflection at the time of total reflection is equal to the angle of incidence. On the other hand, since θd is more acute than 24.4 °, light is emitted from the diamond into the air without causing total reflection.

  The girdle facet is a conical side that is sliced. FIG. 6 is a reflection diagram when there is no inclination in the girdle facet diagram (region indicated by g) (that is, the inclination is 0 degrees with respect to the central axis). When the reflected light from the pavilion side facet is incident on the center of the girdle facet, the area of the pavilion side facet that totally reflects and the area of the pavilion side facet that emits are shown. When reflected light (hereinafter referred to as maximum incident angle reflected light) enters the center of the girdle from the facet on the pavilion side closest to the curette, the incident angle becomes maximum. A region that is incident at an acute angle with respect to light that is incident from the pavilion facet to the center of the girdle facet at an incident angle smaller than the critical angle of diamond to air of 24.4 degrees (hereinafter, referred to as critical incident angle reflected light) is an emission region. Become. FIG. 7 shows a case where the girdle facet (region indicated by g in the figure) has an inclination outward from the bottom edge of the crown (that is, the inclination is 0.1 to 45 degrees outward with respect to the central axis). FIG. As shown in the figure, the maximum incident angle reflected light and the limit incident angle reflected light coincide with each other. From this, it is recognized that when the girdle facet is inclined outside the lowermost edge of the crown, the reflected light at the critical incident angle is shifted so as to approach the reflected light at the maximum incident angle. Since the critical angle exists in both the right direction and the left direction with respect to the vertical line of the girdle facet, the emission region spreads over the entire pavilion facet in the figure. From this fact, when the girdle facet is inclined outside the lowermost edge of the crown, the reflection area is reduced and the emission area is expanded. Since the emission area is expanded, the amount of light emitted from the girdle facet increases. Therefore, the girdle facet of the round-cut diamond in the present embodiment shines sharply in a coronal shape, as compared with the round-cut diamond having a girdle without inclination. For this reason, it becomes a diamond that shines in a direction that was not possible with conventional diamonds.

  The girdle facet is also a part for fixing a fixture for fixing the diamond ore or the already cut cut diamond to the diamond ore or the already cut cut diamond. In order to fix the fixture, a girdle having a surface parallel to the table facet normal, like a conventional girdle, is ground. Therefore, when cutting a diamond ore or a cut diamond that has already been cut, first grasp the diamond with the girdle to finish the processing of the crown side facet and / or the pavilion side facet, and then the girdle facet (table facet normal and It is preferable that the working procedure is for processing (having non-parallel surfaces). In particular, it is desired to process the girdle facet after the crown facet is finished at the earliest. The angle on the acute angle side with the line parallel to the table facet normal of the crown side facet is generally preferably 53.5 degrees to 58.5 degrees (also in the present invention), but the angle on the acute angle side is 58.5 degrees. May be larger. For example, it has been found that 58.5 degrees or more and 75 degrees or less, and more preferably 63 degrees plus or minus 1 degree is preferable. In this way, as the angle of the crown side facet is increased, the amount of light incident from the crown side facet is increased and the amount of light flux emitted from the table facet is further increased. Further, the angle on the acute angle side with the table facet normal to the pavilion side facet is generally (also in the present invention) preferably about 48.2 to 49.4 degrees. This angle is an angle suitable for the light flux incident from the table facet to be totally reflected by the pavilion side facet and to be emitted again from the crown side facet and the table facet. Further, the ratio of the area of the table facet to the area of the crown side facet in the top view of the cut diamond is preferably 52% to 62%: 38% to 48%, but the table facet normal of the crown side facet is suitable. If the angle on the acute angle side with the line parallel to is large, for example, if the angle on the acute angle side is larger than 58.5 degrees, the amount of incident light flux that can be totally reflected by the facet on the pavilion side increases. The said proportion occupied by facets may be less than 52%. For example, it may be about 25% to 52%. In this case, the light emitted from the diamond is typified in the direction normal to the center of gravity of each facet, so that the diamond is configured so that the glitters are concentrated in substantially the same direction.

<Embodiment 2>
<Embodiment 2 of the invention>
The invention in this embodiment is such that the girdle is at least 0.1 degree and 45 degrees inward from the bottom edge of the crown with respect to the center axis passing from the table facet center to the center of the curette surface (however, the pavilion surface serves as the center axis). It is a round cut diamond having girdle facets that are composed of girdle facets that are inclined below, and that increase the total reflection of the luminous flux that is incident from the table facet and reflected by the pavilion side facet with the girdle.

<Embodiment 2 of the invention>
The round-cut diamond according to the present embodiment has a girdle of 0.1 degrees or more and 45 degrees inward of the crown with respect to the center axis passing through the center of the table facet and the center of the curette surface (however, the angle formed by the pavilion surface and the center axis). It has a girdle facet in which the total reflection of the luminous flux incident from the table facet and reflected by the pavilion side facet is increased by the girdle. Descriptions of configurations common to the first embodiment will be omitted, and only configurations characteristic of the present embodiment will be described.

  FIG. 2b shows the inclination (θ2) of the girdle facet with respect to the straight line (C′-C ′) parallel to the central axis (C-C) when the girdle facet is recessed inside the crown. -[Theta] 1 is an angle in the range of 0 to 90 inward with respect to the central axis, and in the present embodiment, is in the range of 0.1 to 30 inward from the lowermost edge of the crown.

  The region on the left side with respect to the 0-degree axis shown in FIG. 3 indicates the case where the girdle facet is recessed inward from the lowermost edge of the crown. The amount of light taken in when the girdle facet is recessed from the crown increases or decreases in accordance with the change from 0 to 90 degrees on the left side as shown in FIG. In the present embodiment, the angle of the girdle facet is the amount of light taken in between 0.1 degrees and 30 degrees in both left and right directions as shown in FIG.

  FIG. 8 shows a case where the girdle facet (region indicated by g in the figure) is tilted inward from the lowermost edge of the crown (that is, the tilt is 0.1 to 45 degrees inward with respect to the central axis). It is a figure. As shown in the figure, the limiting incident angle reflected light is reflected light from the boundary between the pavilion side facet and the girdle facet. From this, when the inclination of the girdle facet is on the inner side of the lowermost edge of the crown, the maximum incident angle reflected light and the limit incident nuclear reflected light are compared with the conventional diamond having no inclination of the girdle facet shown in FIG. Distance increases. Since the reflected light at the critical incident angle approaches the contact direction between the pavilion side facet and the girdle facet, the reflection area of the pavilion side facet expands and the emission area decreases. As compared with the conventional diamond, the emission area is reduced, so that the amount of light emitted from the girdle facet is reduced and the number of irregular reflections in the diamond is increased. For this reason, the contrast between the crown side facet and the girdle (facet) becomes clear and the radiance of the emitting surface is further emphasized, as compared with the conventional diamond in which the girdle facet has no inclination. Therefore, it is evaluated by the observer as a more beautiful diamond as compared with the conventional diamond.

<Embodiment 3>
<Embodiment 3 of the invention>
In addition to the features of the first or second embodiment, the invention of the present embodiment provides that the width of the girdle facet is 0.2% or more and 10.0% or less as a ratio to the height between the curette surface and the table facet. It is a limited diamond.

<Description of Configuration of Third Embodiment>
In the diamond according to the present embodiment, in addition to the configuration described in the first or second embodiment, the width of the girdle facet is 0.2% or more and 10% or less with respect to the height between the curette and the table facet. is there. As shown in FIG. 3, the amount of light taken in by each facet increases as the facet of the diamond faces 90 degrees with respect to the central axis in the state where the facet of the diamond faces up, that is, the facet is parallel to the table facet. When a diamond is displayed in a jewelry store, it is usually displayed with the table facet facing up, and in this state, proof is poured from the heaven side, that is, the ceiling. In addition, when a person wears a diamond ring, the diamond attached to the finger is noticeable when the fingers are lifted to the upper body, but the diamond table facets that are put on the finger in many postures are in the sky. Will turn to. For example, when holding something in your hand, putting your hand on the table, just before shaking hands with the other party, eating with a knife or fork in many cases, the table facet is heavenly. Turn. Therefore, it is preferable to cut the diamond so that the brilliance of the diamond becomes optimum with the table facet facing up. Then, the girdle facet located on the side surface of the diamond is a part where the amount of light taken in is small. Therefore, as the ratio of girdle facets to the whole diamond increases, the amount of light taken in decreases. Therefore, the width of the girdle facet is preferably 10% or less with respect to the height between the curette and the table facet. On the other hand, the brightness in the horizontal direction is best emitted by the girdle facets, which are the facets in the horizontal direction, so it is better to have a certain width. Otherwise, it becomes difficult to visually recognize the linear light traces. Therefore, the width of the girdle facet is preferably 0.2% or more with respect to the height between the curette and the table facet.

<Embodiment 4>
<Embodiment 4 of the Invention>
According to the invention of this embodiment, in addition to the features of the first to third embodiments, each facet other than the table facet in the crown is arranged asymmetrically with respect to the central axis in front view of the table facet. , The facets of the pavilion other than the curette are arranged point-symmetrically with respect to the central axis.

<Embodiment 4 of the Invention>
According to the invention of this embodiment, in addition to the configurations described in the first to third embodiments, each facet other than the table facet of the crown is arranged asymmetrically with respect to the central axis in front view of the table facet. , The facets of the pavilion other than the curette are arranged symmetrically with respect to the central axis. A typical diamond is constructed so that the facets of the crown are point-symmetric with respect to the central axis passing through the center of the table facet and the curette. The configuration of this embodiment does not depend on any one of the configurations of the first to third embodiments and may be an independent configuration.

  As shown in FIG. 9a, when the representative light is emitted from the point-symmetrical crown-side facet, the representative light is compared with the case where the representative light is emitted from the non-point-symmetrical crown-side facet. Even if the overlapping ratio is high and the brightness is the same, the glitter (which can be represented by the number of visible lines and the number of visible points of the representative light) is the latter, that is, the crown side facet is asymmetric with respect to the central axis. It is larger (more) when it is placed in. If the total brightness is the same, the greater (more) the sparkle is, the higher the aesthetic appearance of the observer is.

  Furthermore, the crown side is point-symmetrical, while the pavilion side is point-symmetrical. Since the pavilion side mainly plays a role of substantially totally reflecting the light incident from the crown side, the contribution to the viewer for viewing is low. On the other hand, cutting a diamond requires a skilled skill, and it is difficult to cut facets asymmetrically. Therefore, it does not matter whether the function of reflecting the incident light in the diamond is point-symmetrical or non-point-symmetrical. Therefore, the point-symmetrical structure that is easy to cut is advantageous in manufacturing. It is advisable to divide the cutting process into a process for a worker with a high degree of skill and a process for a worker with a lower degree of skill, the former for the crown side work and the latter for the pavilion side work. Since the point-symmetrical pavilion process is easier, it is preferable to arrange the pavilion cutting process before the crown cutting process. Also, the diamond pavilion is cut while looking at the balance, so in some cases it may be possible to proceed with the work ahead of the pavilion, such as pavilion → crown → pavilion → crown.

<Embodiment 5>
<Embodiment 5 of the Invention>
In addition to the features described in the first to fourth embodiments, the invention in the present embodiment specifies that the number of cut surfaces to be cut in a round cut is 55 crowns and 88 pavilions. Characterize.

<Embodiment 5 of the invention>
FIG. 10: is a figure which shows an example of the ideal cut of the round cut diamond in this embodiment. As shown in the figure, in addition to the structure described in any one of the first to fourth embodiments, the round-cut diamond according to the present embodiment has a table facet (1001) having a hexagonal shape, excluding the girdle facet. The number of facets constituting the crown (1002) is 54 except for the table facets, and the number of facets constituting the pavilion (1003) is 32 without counting the curette except the girdle facets. The total number of facets is 88, including table facets and girdle facets. Even if the curette forms a surface, the emitted light cannot be viewed, so it is not counted as a surface.

  If the number of facets formed on the crown side is 55 and the number of facets formed on the pavilion side is 33, the shape of the facet and the angle of the facet are not limited. However, in order to make the brilliance of diamonds most attractive, it is desirable that light be reflected uniformly. Therefore, it is preferable that the facets are regularly arranged. That is, for example, for the crown side facet, when the table facet is the starting point, the facets that are in contact with the sides of the table facet have the same shape, the same size, and the same bevel angle, All facets that contact the table facet only at the vertices have the same shape, the same size, and the same beveled angle. Most preferably, they have the same shape, the same size, and the same bevel. Facets that have different conditions in relation to the table facets do not have to be configured with the same shape, the same size, and the same bevel. Regarding the pavilion side facets, when the curette surface is used as the starting point, all facets that satisfy the same condition in relation to the curette surface are configured with the same shape, the same size, and the same bevel. Is most desirable.

 Furthermore, when the cut structure of the round cut in the present embodiment is expressed by a plane, it is desirable that the structure is as shown in FIG. As for the facets of the crown, as shown in the upper part of FIG. 10, the table facet is composed of nine triangular first facets (1004) each side of which is one of the nine sides of the table facet. Nine hexagonal vertices as their own vertices, and the other two portions are nine quadrangular second facets (1005) that do not touch the table facets, and a quadrangle that touches only one vertex of the first facet and the first facet. Of the third facet (1006), four fourth facets (1007) of a quadrangle having one side of the third facet as its own side, one side of the fourth facet and another side of the fourth facet. It is composed of nine triangular fifth facets (1008) which are the sides of itself. And, when a straight line is drawn from a certain vertex of the table facet so as to intersect with the central axis, the straight line passes through the vertices of all the first to fifth facets. Is the ideal configuration. As an example of such a configuration, a straight line drawn so as to pass through the central axis at an angle of 20 degrees with respect to a straight line drawn so as to pass through the central axis from the apex of the table facet And all facets from the first to the fifth facet are configured to pass through the vertices.

  As for the facet of the pavilion, as shown in the figure at the bottom of Fig. 10, with the straight line (1009) passing through the curette as the starting point, another curette with a distance of 22.5 degrees from the starting straight line Draw an auxiliary straight line (1010) that passes through, divide the auxiliary straight line into three, and set the dividing points of the auxiliary line as the first dividing point (1011) and the second dividing point (1012) in order from the side closer to the curette. Draw a first sentence division point and a first connection line (1013) that connects the end point of the straight line that is the starting point, which is the shorter distance from the first division point, and parallel to the first connection line from the second division point. It is constructed by repeating the same form when a line that becomes a starting line is drawn (1014) and then a line starting from an auxiliary line is repeated.

  FIG. 11 is a diagram reproducing an experimental result photograph showing light reflection when an irradiation experiment for irradiating a laser on the 88-sided round-cut diamond in the present embodiment. FIG. 12 is a diagram reproducing an experimental result photograph showing light reflection when performing an irradiation experiment of irradiating a laser on a conventional 58-sided (counting the curette as a surface) round-cut diamond. As is clear from comparison between FIG. 11 and FIG. 12, the number of light rays reflected in FIG. 11 is relatively large. The number of reflected rays is the amount of diamond shine. Therefore, as shown in FIG. 11, it can be said that the 88-round round-cut diamond, which has a relatively large number of reflected rays, has more brilliance than the 58-cut.

  FIG. 15 shows the results of a questionnaire in which the conventional cut diamonds and the diamonds of the fifth and sixth embodiments were shown at the same time, and the order of the strongest shine was 1, 2, and 3, respectively. As shown in the table, when comparing the brilliance of the conventional cut diamond and the diamond of the fifth embodiment, all the people who responded to the questionnaire answered that the brilliance of the fifth embodiment is strong. As described above, it can be seen from the eyes of the observer that the brilliance of the diamond of the fifth embodiment is increased as compared with the conventional cut diamond.

  FIG. 16 shows the results of a questionnaire in which the conventional diamonds and the diamonds of the fifth and sixth embodiments are shown at the same time, and the preferred designs are 1, 2 and 3 in the order of preference. As shown in the table, comparing the appearance preferences of the conventional cut diamond and the diamond of the fifth embodiment, all the people who responded to the questionnaire found that the design of the fifth embodiment has a better appearance than the conventional diamond crest. It is recognized that he is judged to be beautiful.

<About diamond value evaluation criteria>
Here, the diamond value evaluation standard will be described. The current handling is that the only standard for attaching a certificate to a diamond is what meets the so-called 4C standard. 4C is clarity, color, cut, carat weight. Points are set for each stage of these four elements, and the points of each element are totaled to evaluate the value of the diamond as a whole. Therefore, the value of diamond is determined by judging each element in a complex way.

  "Clarity" is the transparency of a diamond. Clarity is evaluated based on the relative small number of internal features called inclusion (inclusion) of natural diamonds and surface features called blemishes. Blemish also includes scratches and chips on the surface of the diamond. Clarity features help distinguish between natural and artificial diamonds, and because no two diamonds have exactly the same inclusions in exactly the same place, a diamond is identical to a previously identified diamond. It can be used as a mark when determining whether or not it is. The diamonds that are judged to have the highest rating are those that have no visible inclusions or blemishes when observed under a 10 × magnification by a skilled and experienced appraiser. Higher clarity also increases the price of diamonds per carat if all other factors that determine value are equal. Clarity is evaluated by comprehensively evaluating the size, number, position, nature, color, and relief (outline, visibility) of inclusions and blemishes. The relative importance of each factor varies from diamond to diamond. For example, inclusions that are offset to the sides of a stone are considered to have less impact on clarity than inclusions of the same size directly under the table. In such a case, it can be said that the position is the determining factor of the evaluation.

  "Color" is the color of a diamond. Subtle differences in color can have a large impact on a diamond's value, and two diamonds of similar clarity, weight, and cut can differ in value only by their color. Diamonds come in many colors. Colorless to pale yellow to pale brown diamonds are said to be in the normal color range. In the normal color range, the more colorless the diamond, the more valuable it is. Also, many diamonds reflect visible light called fluorescence when irradiated with ultraviolet light. Fluorescence includes blue, white, yellow, orange and the like. If the fluorescence is too strong, the stone may appear cloudy, which is called "oily" and reduces the value of the diamond.

  “Cut” is an evaluation of diamond proportion (shape and finish). The cut is deeply related to the brightness of the diamond. The light that enters the diamond becomes a brighter diamond due to the excellent refractive index of the diamond and the ideal proportions determined from the refractive index. A good cut will be brighter unless there are large scratches or inclusions that block the light path inside the diamond.

  "Carat" is a unit of jewel weight (ct), which refers to the weight of a diamond, not its size. One carat is fixed at 200 grams.

  As shown in the above table or criteria, it is only in the field of cutting that among the factors that determine the value of diamond, it is possible to make a difference by human skill. Therefore, in order to make the diamond of higher value, it is preferable to make a cut that can further enhance the brilliance of the diamond. The 88-sided cut in the present embodiment has more brilliance than the conventional 58-sided cut, and can further enhance the value as a diamond.

<Sixth Embodiment>
<Embodiment 6 of the Invention>
In addition to the features described in the first to fourth embodiments, the invention in the present embodiment specifies that the number of cut surfaces to be round-cut is 37 crowns, 26 pavilions, and 63 total surfaces. Characterize.

<Embodiment 6 of the invention>
FIG. 13: is a figure which shows an example of the ideal cut of the round cut diamond in this embodiment. As shown in the figure, in the round-cut diamond according to the present embodiment, in addition to the configuration described in any of the first to fourth embodiments, the table facet (1301) is a hexagon, and the girdle facet is excluded. The number of facets forming the crown (1302) is 36 except for the table facets, and the number of facets forming the pavilion (1303) is 25 except for the girdle facets and counting the curette as a face. The total number of facets is 63 faces including table facets and girdle facets. In addition, when the curette is not counted as a surface, it is 62 surfaces.

  Also for the land-cut diamond in the present embodiment, if the number of facets formed on the crown is 37 and the number of facets formed on the pavilion is 25 with the culet as the face, the shape of the facet and the facet angle Is not limited. Furthermore, the most beautiful shine can be obtained when facets that satisfy the same condition in relation to the table facet or the curette surface have the same shape, the same size, and the same bevel angle. Identical to cut diamonds.

  Furthermore, when the cut structure of the round cut in the present embodiment is expressed by a plane, it is desirable that the structure is as shown in FIG. As for the facets of the crown, as shown in the upper diagram of FIG. 13, nine triangular first facets (1304) each having one side of the nine sides forming the table facet as one piece, and the table facet are formed. Nine quadrangular second facets (1305) that do not contact the table facets in the other parts, and a triangular third facet (1306) having one side of the second facet as its own. ) 18 pieces. When a straight line is drawn from a certain vertex of the table facet so as to intersect with the central axis, the straight line passes through the vertexes of all facets from the first to the third. Is the ideal configuration. As an example of such a configuration, a straight line drawn so as to pass through the central axis at an angle of 20 degrees with respect to a straight line drawn so as to pass through the central axis from the apex of the table facet And all facets from the first to the third facet are configured to pass through the vertices.

  As for the facet of the pavilion, as shown in the diagram at the bottom of Fig. 13, from the straight line (1307) passing through the curette as the starting point, another curette spaced 22.5 degrees from the starting straight line Draw an auxiliary straight line (1308) that passes through, divide the auxiliary straight line into two, and divide the auxiliary line (1309) A connecting line (1310) that connects the end point of the straight line that is the shorter distance from the division point Then, the same configuration is repeated when a straight line starting from the auxiliary line is drawn.

  FIG. 14 is a diagram reproducing an experimental result photograph showing reflection of light when an irradiation experiment for irradiating a laser on a 63-sided round-cut diamond in the present embodiment. As described above, FIG. 12 is a diagram showing light reflection when an irradiation experiment of irradiating a laser on a 58-sided round-cut diamond is performed. As is clear from comparison between FIG. 14 and FIG. 12, the number of light rays reflected by FIG. 14 is relatively large. The number of reflected rays is the amount of diamond shine. Therefore, as shown in FIG. 14, it can be said that the 63-sided round-cut diamond, which has a relatively large number of reflected rays, has more brilliance than the 58-sided cut. As described above, it is considered that the diamond having the same condition other than the cut has higher value when the brilliance is stronger, and the 63-face cut in the present embodiment has a brilliance higher than that of the conventional 58-face cut. It is increasing, and it is possible to further increase the value as a diamond.

  As shown in FIG. 15, when comparing the brilliance of the conventional cut diamond and the diamond of the sixth embodiment, all the respondents to the questionnaire answered that the brilliance of the sixth embodiment is strong. As described above, it is recognized that the brilliance of the diamond of claim 6 is higher than that of the conventional cut diamond as seen by the observer.

  As shown in FIG. 16, when comparing the appearance preference of the conventional cut diamond and the diamond of the sixth embodiment, all the people who responded to the questionnaire found that the design of the sixth embodiment was better than the conventional diamond pattern. It is recognized that they are judged to be beautiful in appearance.

<Embodiment 7>
<Embodiment 7 of the Invention>
Inclining the girdle from the center of the table facet to the center axis passing through the center of the curette surface at 0.1 degrees or more and 45 degrees or less (however, limited to an angle smaller than the angle formed by the crown surface and the center axis) Round cut that forms a rough gemstone or other designed diamond by grinding the girdle facet with the girdle facet that reduces the total reflection of the light beam that enters from the table facet and is reflected by the facet on the pavilion side. It is a manufacturing method of diamond.

<Embodiment 7 of the invention>
The invention in this embodiment is such that the girdle is outside the crown with respect to the central axis passing through the center of the curette surface from the center of the table facet at 0.1 degrees or more and 45 degrees (provided that the angle between the crown surface and the central axis is smaller than that described above). (Limited to angles) A girdle facet that is composed of girdle facets that are inclined below, and that reduces the total reflection of the light beam that is incident from the table facet and reflected by the facet on the pavilion side with a girdle, is a diamond designed by rough diamond or other cut Is formed by grinding.

<Embodiment 7 Configuration Description>
"Grinding formation" means removing (cutting) or / and polishing a rough diamond or a diamond that has already been cut to make the surface to be removed smooth and shape the surface to be removed. It means to make the boundary between deleted surfaces stand out.

  Specifically, "cleaving", which is a cutting method using "cleavage", and "sewing", in which diamond powder is cut along the softest hexahedral surface and the next softest dodecahedral surface inside the rough stone. And so on. Then, a step of polishing and finishing is performed. The process is roughly divided into two steps. The cutting process has become more accurate with the use of specialized equipment. Furthermore, the girdle is decided by brouting (body cutting), and the maximum width of the finished diamond is decided at this stage. Then, when the table is sawed and cut out, the faceting work for finishing each surface is started. After rough faceting, finish polishing is performed. At this stage, the final angle adjustment and polishing surface adjustment are finely performed, and the diamond is nearing completion.

  Alternatively, old cut diamonds may be reshaped, and in this case, the shapes of the surfaces may be adjusted by only the removal or the polishing to make the boundary between the adjacent deleted surfaces stand out. The tool used for grinding and forming may be a diamond grindstone, a laser (rough cut of rough stone), or the type thereof is not limited as long as it has the ability to remove and polish diamond.

<Embodiment 8>
<Embodiment 8 of the invention>
The invention in this embodiment is such that the girdle is 0.1 degrees or more and 45 degrees inward of the crown with respect to the center axis passing through the center of the curette surface from the center of the table facet (provided that the angle between the pavilion surface and the center axis is greater than that of the center axis). (Limited to a small angle) The girdle facet, which is composed of inclined girdle facets below and which increases the total reflection of the light beam incident from the table facet and reflected by the pavilion side facet with the girdle, was designed with rough diamond or other cuts It is a method for manufacturing a round-cut diamond in which a diamond is formed by grinding.

<Embodiment 8 of the invention>
The invention in this embodiment is such that the girdle is 0.1 degrees or more and 45 degrees inward of the crown with respect to the center axis passing through the center of the curette surface from the center of the table facet (provided that the angle between the pavilion surface and the center axis is greater than that of the center axis). (Limited to a small angle) The girdle facet, which is composed of inclined girdle facets below and which increases the total reflection of the light beam incident from the table facet and reflected by the pavilion side facet with the girdle, was designed with rough diamond or other cuts Grind and form diamond.

<Embodiment 9>
<Embodiment 9 of the invention>
The invention in this embodiment is, in addition to the features of the seventh or eighth embodiment, a diamond manufacturing method in which the width of the girdle facet is limited by the ratio to the height difference between the curette surface and the table facet.

<Embodiment 9 of the invention>
In the invention according to the present embodiment, in addition to the configuration described in the seventh or eighth embodiment, the width of the girdle facet is 0.2% or more and 10% or less with respect to the height between the curette surface and the table facet. Grind diamonds designed with rough diamonds or other cuts as in.

<Embodiment 10>
<Embodiment 10 of the invention>
In addition to the features of the seventh to ninth embodiments, the invention in this embodiment is such that each facet other than the table facet in the crown is arranged asymmetrically with respect to the central axis in front view of the table facet. It is a method of manufacturing a diamond.

<Embodiment 10 of the invention>
According to the invention of this embodiment, in addition to the configuration described in the seventh or ninth embodiment, each facet other than the table facet of the crown is arranged asymmetrically with respect to the central axis in front view of the table facet. Grind diamonds that are designed with rough diamonds or other cuts as.

<Embodiment 11>
<Eleventh Embodiment of the Invention>
In addition to the features described in the seventh to tenth embodiments, the invention in the present embodiment includes the number of cut surfaces to be cut in a round cut of 55 crowns and 33 pavilions, which is 88 in total. It is a manufacturing method.

<Embodiment 11 of the invention>
In addition to the configuration according to any one of the seventh to tenth embodiments, the configuration of the invention in the present embodiment is such that the table facets are hexagonal, and the number of facets constituting the crown excluding the girdle facet is the table. There are 54 faces excluding facets, and the number of facets that make up the pavilion is 32 faces, excluding the girdle facets, not counting the curette, and the total number of facets is 88 faces including table facets and girdle facets. Grind a rough diamond or other designed diamond as in the cut.

<Embodiment 12>
<Embodiment 12 Overview of the invention>
In addition to the features described in the seventh to tenth embodiments, the invention in the present embodiment specifies the number of cut surfaces to be cut in a round cut as 37 crowns, 26 pavilions, and 63 total diamonds. It is a manufacturing method.

<Embodiment 12 of the invention>
According to the invention of this embodiment, in addition to the features described in any of Embodiments 7 to 10, the table facet is a hexagon, and the number of facets constituting the crown excluding the girdle facet is equal to that of the table facet. Except for the girdle facets, the facets that make up the pavilion are 25 faces, including the curettes, and the total number of facets is 63 faces including table facets and girdle facets. Grind and form rough or other cut designed diamonds.

0101 Table facet 0102 Crown 0103 Pavilion 0104 Crown side facet 0105 Girdle facet 0106 Curette (surface)
0107 Pavilion side facet 0108 Crown bottom edge

Claims (12)

  The girdle is 0.1 degrees or more and 45 degrees outside the lowermost edge of the crown with respect to the central axis passing from the center of the table facet to the center of the curette surface (however, the angle is limited to an angle smaller than the angle formed by the central surface and the central axis). ) A round-cut diamond having a girdle facet that is composed of inclined girdle facets below and has a girdle that reduces the total reflection of the light beam that enters from the table facet and is reflected by the pavilion side facet.   The girdle is 0.1 degrees or more and 45 degrees inward from the bottom edge of the crown with respect to the center axis passing through the center of the table facet and the center of the curette surface (however, limited to an angle smaller than the angle formed by the pavilion surface and the center axis). ) A round-cut diamond having a girdle facet that is composed of inclined girdle facets below, and that increases the total reflection of the luminous flux incident from the table facet and reflected at the pavilion side facet with the girdle.   The round diamond according to claim 1 or 2, wherein a width of the girdle facet is 0.2% or more and 10% or less with respect to a height between the curette surface and the table facet.   Each facet except the table facet of the crown is arranged in a point symmetry with respect to the center axis in front view of the table facet, and each facet except the curette of the pavilion is arranged in point symmetry with respect to the center axis. The round cut diamond according to any one of claims 1 to 3.   The table facets are hexagonal, the number of facets constituting the crown excluding the girdle facets is 54 except the table facets, and the number of facets constituting the pavilion is the curette except the girdle facets. The round cut diamond according to any one of claims 1 to 4, which has 32 faces, not counting, and has 88 facets including a table facet and a girdle facet.   The table facets are hexagonal, the number of facets constituting the crown excluding the girdle facets is 36 except the table facets, and the number of facets constituting the pavilion is the curette except the girdle facets. The round-cut diamond according to any one of claims 1 to 4, wherein the round-cut diamond has 25 faces, and the total number of facets is 63 faces including table facets and girdle facets.   Inclining the girdle from the center of the table facet to the center axis passing through the center of the curette surface at 0.1 degrees or more and 45 degrees or less (however, limited to an angle smaller than the angle formed by the crown surface and the center axis) Round cut that forms a rough gemstone or other designed diamond by grinding the girdle facet with the girdle facet that reduces the total reflection of the light beam that enters from the table facet and is reflected by the facet on the pavilion side. Diamond manufacturing method.   Inclining the girdle from the center of the table facet to the center axis passing through the center of the curette surface within 0.1 degree or more and 45 degrees (however, limited to an angle smaller than the angle formed by the pavilion surface and the center axis) Round cut that forms a gemstone facet or other designed diamond by grinding the girdle facet that increases the total reflection of the luminous flux incident from the table facet and reflected by the facet on the pavilion side with the girdle Diamond manufacturing method.   The gemstone facet has a width of 0.2% or more and 10% or less with respect to the height between the curette surface and the table facet. The method for manufacturing a round-cut diamond according to claim 7 or claim 8.   Each of the facets of the crown except the table facets is formed by grinding a rough diamond or a diamond designed by another cut so as to be arranged in a point symmetry with respect to the center axis in a front view of the table facet. To the method for producing a round-cut diamond according to claim 9.   The table facets are hexagonal, the number of facets constituting the crown excluding the girdle facets is 54 except the table facets, and the number of facets constituting the pavilion is the curette except the girdle facets. 11. Any one of claims 7 to 10 in which rough diamonds or diamonds designed with other cuts are formed by grinding so that the total number of facets is 32 faces, and the total number of facets is 88 faces including table facets and girdle facets. The method for producing a round-cut diamond described in Kaichi.   The table facets are hexagonal, the number of facets constituting the crown excluding the girdle facets is 36 except the table facets, and the number of facets constituting the pavilion is the curette except the girdle facets. 11. Grinding a rough diamond or a diamond designed by another cut so that the total number of facets is 25 and the total number of facets is 63 including the table facet and the girdle facet. The method for producing a round-cut diamond described in 1.

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