JP2008018120A - Two-staged pavilion decorative diamond - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-staged pavilion decorative diamond, very bright and with a number of reflection patterns when the diamond is observed through a table facet and through a surface of a crown. <P>SOLUTION: The diamond has the same crown as a round brilliant cut diamond, and has first and second pavilions divided by a horizontal dividing plane. A lower girdle facet and a pavilion main facet are bent by the horizontal dividing plane between the first and second pavilions, and the angle of the first pavilion is larger than the angle of the second pavilion. The two-staged pavilion decorative diamond sparkles more brilliantly than the conventional round brilliant cut diamond, and has double reflection patterns. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cut design for decorative diamond, and more particularly to a novel cut design that is more beautiful for those who observe the diamond.

  Round brilliant cut ornamental diamonds and jewelry with a 58-hedron have been obtained in order to cut diamonds for decoration and to obtain shiny diamonds and jewelry.

  The ideal cut proposed by mathematician Turkey Fusky as a design to increase the brightness of ornamental diamonds with round brilliant cuts is a pavilion angle of 40.75 degrees, a crown angle of 34.50 degrees, and a table diameter of the girdle. The contrast is 53%. There is what is called a GIA (abbreviation of Geographical Institute of America) system as a design developed from that.

The inventors have examined cuts that increase the brightness of decorative diamonds. When observing a round brilliant cut diamond from the table facet, the light incident on the crown surface and emitted from the crown surface is incident on the table facet. As a cut design in which the light emitted from the crown surface and the light incident on the crown surface and emitted from the table facet can be observed simultaneously, the pavilion angle p is 45 ° or less and 37.5 ° or more,
The crown angle (c) is set to −3.5 × p + 163.6 ≧ c ≧ −3.8333 × p + 174.232
The thing which exists in the range which satisfies is proposed in patent document 1. FIG. The center value is a pavilion angle p of 38.5 ° and a crown angle (c) of 27.92 °. Since round brilliant cut diamonds place importance on the brightness of the crown face as well as the brightness of the table facets, the diameter of the table facets is 40 to 60% compared to the girdle diameter. 33-60%.

  The brightness of the decorative diamond is detected by the observer when light enters the diamond from the outside and the incident light is reflected inside the diamond. The magnitude of diamond shine is determined by the amount of reflected light. The amount of reflected light is usually evaluated by the amount of physical reflected light.

However, human perception is not determined by the amount of physical reflection. In order for a person observing diamond to feel beautiful, the amount of light felt by the person, that is, the amount of physiologically or psychological visual perceptual reflection light, needs to be large. Regarding the amount of light perceived by humans, there are Fechner's law and Stevens' law (see Non-Patent Document 1). According to Fechner's law, the amount of visual perception light is the logarithm of physical light quantity. When the light source is regarded as a point light source and Stevens' law is applied, the square root of the physical light quantity is the amount of visual perceptual light. Although it is quantitatively different based on either the Fechner or Stevens law, many of the conclusions are the same and are generally error-free. Therefore, in order to evaluate the amount of reflected light of the diamond, the inventors obtained the amount of visual perceptual light based on Stevens's law, and when it was reflected, evaluated the brightness of the diamond as the amount of visual perceptual reflected light. Decided to do. Although the amount of reflected light from diamond varies depending on the illumination conditions, as a practical condition, incident light from a flat light source with uniform brightness that is blocked by the observer and incident light coming from far away In addition, Patent Document 2 proposes to evaluate the amount of effective visual perceptual reflected light using the remaining reflected light of incident light, and the design of the brilliant cut diamond capable of increasing the amount of effective visual perceptual reflected light. Proposed in that.
Japanese Patent No. 3,643,541 JP 2003-310318 A Published by Takao Matsuda Baifukan "Visual Perception" 2000, 10-12 pages

  The present invention was completed by studying the diamond round brilliant cut design to further increase the amount of effective visual perceptual reflected light. Accordingly, an object of the present invention is to provide a decorative diamond having a two-stage pavilion with a large number of reflection patterns, which is very bright when the diamond is observed from a table facet and a crown surface. is there.

A two-stage pavilion decorative diamond according to the present invention comprises a circular or polygonal girdle having an upper horizontal cross section surrounded by an upper outer periphery and a lower horizontal cross section surrounded by a lower outer periphery and parallel to the upper horizontal cross section;
A crown having a regular octagonal table facet on the horizontal horizontal section of the upper part of the girdle and having a substantially truncated polygonal pyramid formed upward from the girdle and forming the top surface of the truncated polygonal pyramid; ,
It has a pavilion that is formed downward from the girdle below the girdle lower horizontal section and has a substantially polygonal pyramid with a bottom vertex,
The pavilion consists of a first pavilion and a second pavilion separated by a horizontal dividing plane parallel to the girdle lower horizontal section.

  The crown has 8 bezel facets, 8 star facets and 16 upper girdle facets with table facets. The first pavilion has eight first pavilion main facets and sixteen first lower girdle facets. The second pavilion has 8 second pavilion main facets and 16 second lower girdle facets.

In the diamond of the present invention, a straight line passing from the bottom vertex of the polygonal pyramid pavilion to the center of the table facet is the Z axis,
The plane that includes the Z axis and passes through each of the 8 vertices of the table facet is the first plane,
A straight line that passes through the point where one of the first planes intersects the outer periphery of the lower part of the girdle and is perpendicular to the Z axis,
The first plane perpendicular to the Z axis and the X axis passes through the point where it intersects the outer periphery of the lower part of the girdle, and the straight line perpendicular to the Z axis and the X axis includes the Y axis and the Z axis. A plane that bisects the corner is defined as a second plane.

  At the crown, each bezel facet is a quadrilateral plane with the vertex of the table facet and the point where the first plane passing through the apex intersects the outer periphery of the upper part of the girdle, and the quadrilateral plane is the other two Each pair of vertices is on each of the adjacent second planes, and shares one vertex of the other two paired vertices with the adjacent bezel facet. Each star facet is an isosceles triangle formed by a vertex shared by two adjacent bezel facets with one side of the table facet as the base and both ends of the base face as vertices. Each upper girdle facet is a triangle formed by one side that intersects one end of the upper side of the girdle and one end of each side of the bezel facet, and a point where the second plane passing through the other end of the side intersects the outer periphery of the girdle upper side It is.

  In the first pavilion, each first pavilion main facet is an isosceles triangle having a vertex at a point where the first plane intersects the outer periphery of the lower part of the girdle and a base perpendicular to the first plane on the horizontal dividing plane. Each first lower girdle facet has a girdle lower outer peripheral portion sandwiched between adjacent first and second planes, and a hypotenuse of an isosceles triangle of a first pavilion main facet having a vertex on the first plane. , A quadrilateral plane surrounded by a side on the second plane passing through the end on the second plane of the lower periphery of the girdle and a side on the horizontal dividing plane passing through the base of the isosceles triangle .

  In the second pavilion, each second pavilion main facet is a pentagonal plane symmetrical with respect to the first plane having a vertex at the pavilion base vertex and sharing the base of the isosceles triangle of the first pavilion main facet, The pentagonal plane has other vertices on each adjacent second plane and shares the adjacent second pavilion main facet with one side and two vertices. Each second lower girdle facet has a vertex of a second pavilion main facet on a second plane, an end of the bottom side of the second pavilion main facet, and an edge of the second pavilion main facet having them as ends. , And a side formed on the horizontal dividing plane of the first lower girdle facet, and shares a side on the second plane with the adjacent second lower girdle facet.

And in the two-stage pavilion decorative diamond of the present invention, the first pavilion angle (p1) between the first pavilion main facet and the girdle lower horizontal section is 40-47 °,
In the graph in which the first pavilion angle (p1) is taken on the horizontal axis and the crown angle (c) between the bezel facet and the girdle lower horizontal section is taken on the vertical axis, (p1, c) is (40, 27.8) Crown angle (c) in a region sandwiched between a straight line connecting two points (47, 8.9) and a straight line connecting two points (40, 32.8) and (47, 15.0) (c )
In the graph in which the first pavilion angle (p1) is taken on the horizontal axis and the second pavilion angle (p2) between the second pavilion main facet and the girdle lower horizontal section is taken on the vertical axis, (p1, p2) is (40, 36.7) and (44, 37.0), a straight line connecting the two points, and (44, 37.0) and a straight line connecting the two points (47, 38.1), and (40 38.7) and (47, 41.3) have a second pavilion angle (p2) in a region sandwiched between the two points.

  The X-axis coordinate (del) of the regular octagonal vertex of the table facet on the X-axis is 0.9 to 1.2 when the X-axis coordinate of the point where the outer periphery of the girdle crosses the X-axis is 2.0. .

  The reflection rating index of the two-stage pavilion ornamental diamond of the present invention is much greater than the reflection rating index 400 of an excellent grade round brilliant cut diamond.

  In addition, the number of reflection patterns of the two-stage pavilion decorative diamond of the present invention is nearly twice the number of reflection patterns 67 of excellent grade round brilliant cut diamonds, and the number of reflection patterns of round brilliant cut diamonds proposed by the inventors is 85. Bigger than.

  As described above, the two-stage pavilion decorative diamond of the present invention is excellent not only for decoration because it has not only a larger brightness of reflected light but also a larger number of reflection patterns.

Structure of Diamond with Two-Stage Pavilion Diamonds 100 with two-step pavilions according to the present invention are shown in FIGS. 1 to 3 and their cross-sectional explanatory views are shown in FIG. 2 is a side view and FIG. 3 is a bottom view. Here, the upper surface of the diamond 100 is a regular octagonal table facet 112, and the girdle 120 has a circle or a polygon, and is surrounded by an upper horizontal section 124 surrounded by a girdle upper outer periphery 122 and a girdle lower outer periphery 126. Between the lower horizontal section 128 parallel to the upper horizontal section 124. A crown 110 having a substantially truncated polygonal pyramid formed upward from the girdle 120 is formed at the upper part of the upper horizontal section 124 of the girdle, and a regular octagonal table facet 112 forms the top surface of the truncated polygonal pyramid. . There is a pavilion 130 having a substantially octagonal pyramid formed downward from the girdle 120 at the lower part of the horizontal section 128 of the lower part of the girdle, and there is a part called a curette at the center bottom vertex G thereof. There are usually eight bezel facets 114 on the outer periphery of the crown 110, and eight star facets 116 are formed between the outer periphery of the table and the bezel facets 114, and there are 16 between the girdle 120 and the bezel facets 114. A number of upper girdle facets 118 are formed. The pavilion 130 has a horizontal dividing plane 134 parallel to the girdle lower horizontal section 128 at approximately the middle of its height, so that the pavilion 130 has a first pavilion 132 above the horizontal dividing plane 134 and a horizontal dividing plane 134. It is divided into a second pavilion 142 below. Eight first pavilion main facets 136 are formed on the outer periphery of the first pavilion 132, and sixteen first lower girdle facets 138 are formed between the girdle 120 and the first pavilion main facet 136. Yes. The outer surface of the girdle 120 is perpendicular to the table facet 112. The second pavilion 142 has eight second pavilion main facets 146 and sixteen second lower girdle facets 148 on the outer periphery thereof.

  A straight line passing from the bottom vertex G of the octagonal pyramid pavilion 130 through the table facet center to the Z axis, a plane including the Z axis and passing through each octagonal vertex of the table facet to the first plane 102, and passing through the Z axis A plane that bisects the angle between the first planes 102 is referred to as a second plane 104.

  For the reason of explanation, as shown in FIG. 1 to FIG. 4, an orthogonal coordinate axis (right-handed system) is taken in the diamond 100, and the Z axis passes through the table facet center from the octagonal pyramid pavilion bottom vertex G. (Z axis). A straight line that passes through a point where one of the first planes 102 intersects the girdle lower outer periphery 126 and is perpendicular to the Z axis is defined as an X axis, and a straight line that is perpendicular to the Z axis and the X axis is defined as a Y axis. The origin O of the X, Y, and Z axes is the center of the girdle lower horizontal section 128. The diamond 100 is 8 times symmetric about the Z axis, which is perpendicular to the table facet 112, the girdle upper horizontal section 124, the girdle lower horizontal section 128 and the pavilion horizontal dividing plane 134. In FIG. 4, the Y axis is not shown because it faces from the origin O to the back side of the page.

  The first plane is a ZX plane, a YZ plane, and a plane obtained by rotating those planes by 45 ° around the Z axis, and is shown as 102 in FIGS. The second plane is a plane obtained by rotating the first plane 102 by 22.5 ° around the Z axis, and is shown as 104 in FIGS.

  Referring to FIG. 1, each bezel facet 114 has one apex (for example, A in FIG. 1) of a regular octagonal table facet 112 and a first plane 102 (for example, a ZX plane) passing through the apex A having a girdle upper outer periphery 122. A quadrilateral plane having a point B that intersects with a vertex, and the quadrilateral plane has the other two opposite vertices C and D on each of the adjacent second planes 104, next to each other. It shares a vertex C or D with a certain bezel facet 114. Each star facet 116 is formed by one side AA ′ of the regular octagonal table facet 112 and a vertex C shared by two bezel facets 114 each having both ends A and A ′ as one vertex. Triangle AA'C. Each upper girdle facet 118 has one side (for example, CB) intersecting the girdle upper outer periphery 122 among the sides of the bezel facets 114, and the second plane 104 passing through the other end C of the side has a girdle upper outer periphery 122. A plane formed by intersecting points E.

  2 and 3, each first pavilion main facet 136 of the first pavilion 132 has a vertex at a point F where the first plane 102 (for example, ZX plane) intersects the girdle lower outer periphery 126, and the first plane An isosceles triangle FKK ′ having a base KK ′ perpendicular to 102 on a horizontal dividing plane 134. Each first lower girdle facet 138 includes a first pavilion main facet having a portion FJ of a girdle lower outer periphery 126 sandwiched between adjacent first plane 102 and second plane 104 and a vertex F on the first plane 102. 136 isosceles side FK of the isosceles triangle FKK ′, side JL on the second plane 104 where the portion FJ of the girdle lower outer periphery 126 passes the end J on the second plane 104, and one base of the isosceles triangle FKK ′. This is a quadrilateral FJLK plane surrounded by a side LK on the horizontal dividing plane 134 passing through the vertex K. The first pavilion 132 is a portion of the pavilion 130 sandwiched between the girdle lower horizontal section 128 and the horizontal dividing plane 134, and the outer peripheral surface thereof is composed of eight first pavilion main facets 136 and sixteen first lower girdles. And a facet 138.

  In the second pavilion 142, each second pavilion main facet 146 has a vertex at the pavilion bottom vertex G, and a first plane 102 having the base KK ′ of the isosceles triangle FKK ′ of the first pavilion main facet 136 as a base. With respect to each other, the pentagonal plane having another apex H, H 'on each adjacent second plane 104, the adjacent second pavilion main facet 146, one side GH and two The vertices G and H are shared. Each second lower girdle facet 148 has its apex H of the second pavilion main facet 146 on the second plane 104, the bottom edge K of the second pavilion main facet 146, and its ends H and K. The side HK of the second pavilion main facet 146 is shared with the second pavilion main facet 146, and is a triangle HKL formed by the side HK and the side LK on the horizontal dividing plane 134 of the first lower girdle facet 138. Thus, the adjacent second lower girdle facet 148 and the side HL on the second plane 104 are shared. The second pavilion 142 is a portion of the pavilion 130 between the horizontal dividing plane 134 and the pavilion bottom vertex G, and the outer peripheral surface thereof is formed with eight second pavilion main facets 146 and sixteen second lower girdle facets 148. It consists of and.

  Each bezel facet 114 and each second pavilion main facet 146 are sandwiched between two adjacent second planes 104. A first pavilion main facet 136 lies between two adjacent second planes 104 and is perpendicular to the first plane 102. A common side CE of two adjacent upper girdle facets 118, a common side LJ of two adjacent first lower girdle facets 138, and a common side HL of two adjacent second lower girdle facets 148 are the second plane 104. It's above. Two adjacent first planes 102 share each side face HL with each star facet 116, two upper girdle facets 118 that share side CE, and two first lower girdle facets 138 that share side LJ. Two second lower girdle facets 148 are sandwiched. These two upper girdle facets 118 and these two first lower girdle facets 138 are in substantially opposite positions with the girdle 120 in between.

  Each first plane 102 divides the center of each bezel facet 114, the center of each first pavilion main facet 136, and the center of each second pavilion main facet 146. For this purpose, each bezel facet 114 is substantially opposed to each first pavilion main facet 136 and each second pavilion main facet 146 with the girdle 120 interposed therebetween.

  In the following description, the dimensions of each part of the diamond are expressed with reference to the girdle radius. That is, the X axis coordinate of each part when the X axis coordinate of the point where the girdle lower outer periphery 126 intersects the X axis is 2.0 is shown. The girdle height (h) is a dimension of the girdle 120 in the Z-axis direction, and is represented by a value when the girdle radius is 2.0.

  In the cross-sectional view in the ZX plane shown in FIG. 4, the same parts as those in FIGS. 1 to 3 are denoted by the same reference numerals. Here, the angle between the bezel facet 114 of the crown 110 and the girdle lower horizontal section 128 (XY plane), that is, the crown angle is denoted by c, and the first pavilion main facet 136 of the first pavilion 132 is the girdle lower horizontal section 128 (XY). The angle formed by the surface), that is, the first pavilion angle is indicated by p1. Further, the angle formed by the second pavilion main facet 146 of the second pavilion 142 and the girdle lower horizontal section 128 (XY plane), that is, the second pavilion angle is indicated by p2. In this specification, the bezel facet, star facet, and upper girdle facet on the crown are collectively referred to as the crown surface, and the first and second pavilion main facets on the pavilion and the first and second lower girdle facets are collectively referred to as the pavilion surface. Sometimes.

  The girdle height (h), table radius (del), distance to the star facet tip (fx), distance to the lower vertex of the second lower girdle facet (Gd), and position (ax) of the horizontal dividing plane of the pavilion are As shown in FIG. 1, FIG. 3 and FIG. The table radius (del) is the X-axis coordinate of the regular octagonal apex of the table facet 112 on the X-axis as shown in FIG. 1, and is preferably in the range of 0.9 to 1.2. When the table radius is smaller than 0.9, the light reflected by the first pavilion is difficult to reach the table facet directly, and the table facet becomes dark. On the contrary, if the table radius is larger than 1.2, the crown surface becomes dark. Further, when the table radius is outside the range of 0.9 to 1.2, the number of reflection patterns decreases. Therefore, the table radius (del) is preferably 0.9 to 1.2. The distance (fx) to the star facet tip is the X axis coordinate of the vertex C that the bezel facet 114 intersecting with the first plane including the X axis shares with the adjacent bezel facet 114, and the star facet tip from the Z axis. Is a projection of the distance up to the ZX plane. The distance (Gd) to the lower vertex of the second lower girdle facet in the second pavilion 142 is the X-axis coordinate of the vertex H on the pavilion bottom vertex G side of the second lower girdle facet 148 of the second pavilion 142, and the central axis ( This is a value obtained by multiplying the distance from the Z axis) to the vertex H by cos 22.5 °. Also, in order to represent the location of the horizontal dividing plane 134 that divides the pavilion 130 into the first pavilion 132 and the second pavilion 142, the X axis at the intersection of the outer periphery of the horizontal dividing plane and the first plane including the X axis Coordinates (ax) are used.

  In addition to the table radius, pavilion angle, and crown angle, the crown height, pavilion depth, and total depth may be used to define the size of the diamond. Since the first pavilion angle (p1), the second pavilion angle (p2), and the crown angle (c) are uniquely determined, they are not mentioned in this specification.

Introducing the reflection evaluation index In the following examination, diamond was set so that the Z-axis of the diamond was vertical, and the diamond was observed from above the Z-axis by irradiating with light from a light source uniformly distributed on the horizontal ceiling. To do. Light incident on the diamond table facet and crown surface at an angle of less than 20 ° with respect to the Z axis has a high probability of being blocked by the observer. In addition, light incident at an angle greater than 45 ° with respect to the Z axis has a low probability of being blocked by an obstacle due to attenuation due to distance, and has little contribution to reflection. Therefore, the light quantity of the reflection pattern is obtained in consideration of the contribution rate according to the incident angle of the incident light with respect to the Z axis.

  Human visual perception feels the intensity of a small light spot as a stimulus amount. Therefore, it is necessary to convert the amount of light of the reflection pattern obtained physically into the amount of visual perception that is felt as a stimulus. According to Stevens' law, the amount of visual perception as the stimulus intensity felt by a person in the case of a small light spot is proportional to the square root of the amount of physical light.

Applying this rule, the minimum physical reflected light quantity that can be aesthetically perceived as a unit, the square root of the amount of light for each reflection pattern expressed as a multiple thereof is obtained, and the sum is taken as the reflection evaluation index. When calculating the amount of physical reflected light, cut the diamond radius into 200 equal meshes, determine the amount of reflected light taking into account the contribution rate for each mesh, and add the sum of the same pattern to the physical of the pattern. Is the amount of the reflected light. Since diamond has a radius of about several millimeters, each mesh is several hundred μm ² . Considering the size that can be identified by humans, the visual perception amount was calculated only for a pattern having an area of 100 mesh or more, and the sum was used as the reflection evaluation index.

That is, the reflection evaluation index = Σ {(physical reflection light amount considering the contribution rate for each pattern of 100 mesh or more) / unit of the minimum amount of physical reflection light that can be perceived} ^1/2 . Here, Σ is the total sum of the reflection patterns.

Reflection evaluation index The first pavilion angle (p1) when the girdle radius is 2.0 and the table radius (radius to the octagonal apex) (del) is 1.0 in the two-stage pavilion decorative diamond of the present invention. Is 40 °, 41 °, 43 °, 44 °, 46 °, 47 °, and the reflection evaluation index is obtained by changing the crown angle (c) from 8 ° to 33 °. The relationship with respect to (c) is shown graphically in FIG. 7 with the first pavilion angle (p1) as a parameter. As is apparent from FIG. 7, the crown angle range in which the reflection evaluation index exceeds 430 at the first pavilion angle (p1): 40 ° is 27.8-32.8 °, and the first pavilion angle (p1): 41 °. The crown angle range where the reflection evaluation index exceeds 430 is 23.0 to 30.0 °, and the first pavilion angle (p1): 43 °, the crown angle range where the reflection evaluation index exceeds 430 is 17.0 to 25.2 °. The first pavilion angle (p1) is 44 ° and the crown angle range in which the reflection evaluation index exceeds 430 is 16.1 to 23.9 °, and the first pavilion angle (p1) is 46 ° and the reflection evaluation index exceeds 430. The crown angle range is 11.3 to 17.8 °, and the first pavilion angle (p1) is 47 °. The crown angle range in which the reflection evaluation index exceeds 430 is 8.9 to 15.0 °. FIG. 5 is a graph showing the range of the crown angle (c) where the reflection evaluation index exceeds 430 with respect to the first pavilion angle (p1). The region of the first pavilion angle (p1) and the crown angle (c) is the coordinates of (p1, c) on the graph shown in FIG. 5 when the first pavilion angle (p1) is in the range of 40 to 47 °. It can be seen that it is sandwiched between a straight line connecting (40, 27.8) and (47, 8.9) and a straight line connecting (40, 32.8) and (47, 15.0). . As shown in FIG. 5, it can be seen that a preferable crown angle range in which the reflection evaluation index exceeds 430 varies depending on the value of the first pavilion angle.

  Next, in the two-stage pavilion decorative diamond of the present invention, when the girdle radius is 2.0 and the table radius (del) is 1.0, the first pavilion angle (p1) is 40 °, 41 °, 43 The second pavilion angle of the reflection evaluation index is obtained by changing the second pavilion angle (p2) from 36.7 ° to 41.4 ° with the angle of 44 °, 46 ° and 47 °. The relationship with respect to (p2) is shown graphically in FIG. 8 with the first pavilion angle (p1) as a parameter. As apparent from FIG. 8, the first pavilion angle (p1): 40 °, the second pavilion angle range in which the reflection evaluation index exceeds 430 is 36.7-38.7 °, and the first pavilion angle (p1): 41. The second pavilion angle range in which the reflection evaluation index exceeds 430 at 3 ° is 36.8 to 39.2 °, and the first pavilion angle (p1): the second pavilion angle range in which the reflection evaluation index exceeds 430 at 43 ° is 37. 0 to 39.9 °, first pavilion angle (p1): the second pavilion angle range in which the reflection evaluation index exceeds 430 at 44 ° is 37.0 to 40.4 °, and the first pavilion angle (p1) is 46 °. The second pavilion angle range in which the reflection evaluation index exceeds 430 is 37.6 to 41.0 °, and the first pavilion angle (p1): 47 °, the second pavilion angle range in which the reflection evaluation index exceeds 430 is It is 38.1-41.3 degrees. FIG. 6 is a graph showing the range of the second pavilion angle (p2) in which the reflection evaluation index exceeds 430 with respect to the first pavilion angle (p1). The region of the first pavilion angle (p1) and the second pavilion angle (p2) is such that the first pavilion angle (p1) is 40 to 47 ° and (p1, p2) on the graph shown in FIG. Above the two straight lines in the coordinates, the straight line connecting (40, 36.7) and (44, 37.0) and the straight line connecting (44, 37.0) and (47, 38.1) Thus, it can be seen that it is below the straight line connecting (40, 38.7) and (47, 41.3).

  In addition, it is a conventional excellent grade round brilliant cut diamond, pavilion angle: 41.4 °, crown angle: 32.8 °, girdle radius: 2.0, table radius (del): 1.14, star facet tip distance ( fx): 1.454, lower girdle facet lower tip distance (Gd): 0.4, girdle height (h): 0.12, the reflection evaluation index is about 370, which is an excellent grade round Brilliant cut diamonds never exceed 400. As shown in FIGS. 7 and 8, in the two-stage pavilion decorative diamond of the present invention, the reflection evaluation index exceeds 430 in the range of the first pavilion angle of 40 to 47 °. In FIGS. 7 and 8, the reflection evaluation index level of the conventional example: 400 is indicated by a solid line, and 430 which is higher than the margin under various conditions is indicated by a broken line as the lower limit reflection evaluation index of the present invention. In order to make the reflection evaluation index higher than 430 by appropriately combining the first pavilion angle, the second pavilion angle, and the crown angle, the second pavilion angle and the crown angle are set within the range of the first pavilion angle of 40 to 47 °. It is necessary to set the value in the region shown in FIGS.

Number of reflection patterns A two-stage pavilion decorative diamond according to the present invention. First pavilion angle: 43 °, second pavilion angle: 39 °, crown angle: 20 °, girdle radius: 2.0, table radius (del): 1 FIG. 9 shows a reflection pattern having an area of 100 mesh or more when 0.0 is drawn on the table facet and the crown surface sandwiched between the X axis and the Y axis. The number of reflection patterns was 116. FIG. 10 shows the conventional excellent grade round brilliant cut diamond described above, in which a reflection pattern having an area of 100 mesh or more is drawn on the table facet and the crown surface sandwiched between the X axis and the Y axis. . The number of the reflection patterns was 67. Further, a table facet in which a reflection pattern having an area of 100 mesh or more is sandwiched between an X axis and a Y axis in the round brilliant cut diamond proposed by the present inventors in Patent Document 1 having the parameters described above. FIG. 11 shows what is drawn on the crown surface. The number of reflection patterns was 85.

  As described above, the number of reflection patterns of the two-stage pavilion decorative diamond of the present invention is nearly twice that of the conventional excellent-grade round brilliant cut diamond, and the brilliant cut proposed by the inventors before the present invention. 1.2 times. Therefore, the two-stage pavilion decorative diamond of the present invention is excellent for decoration.

It is a top view of the diamond for a two-stage pavilion decoration by this invention. 1 is a side view of a two-stage pavilion decorative diamond according to the present invention. FIG. It is a bottom view of the diamond for a two-stage pavilion decoration by this invention. FIG. 4 is an explanatory cross-sectional view in the ZX plane of the two-stage pavilion decorative diamond shown in FIGS. 1, 2, and 3. It is a graph which shows the area | region of the crown angle of the two-step pavilion ornamental diamond by this invention, and the 1st pavilion angle, with the 1st pavilion angle on the horizontal axis and the crown angle on the vertical axis. It is the graph which shows the area | region of the 2nd pavilion angle | corner of the two-step pavilion ornamental diamond by this invention, and the 1st pavilion angle, with the 1st pavilion angle on the horizontal axis and the 2nd pavilion angle on the vertical axis. It is a graph which shows the relationship between the reflective evaluation index | exponent of the diamond for two-stage pavilion decoration by this invention, and a crown angle by making a 1st pavilion angle a parameter. It is a graph which shows the relationship between the reflective evaluation index | exponent of the two-step pavilion decoration diamond by this invention, and a 2nd pavilion angle, using a 1st pavilion angle as a parameter. It is a figure which shows the reflective pattern of the diamond for a two-stage pavilion decoration by this invention. It is a figure which shows the reflection pattern of the conventional excellent grade round brilliant cut diamond. It is a figure which shows the reflection pattern of the round brilliant cut diamond which inventors proposed previously in patent document 1. FIG.

Explanation of symbols

100 Diamond 102 First plane 104 Second plane 110 Crown 112 Table facet 114 Bezel facet 116 Star facet 118 Upper girdle facet 120 Girdle 122 Upper outer periphery 124 Upper horizontal section 126 Lower outer periphery 128 Lower horizontal section 130 Pavilion 132 First pavilion 134 Horizontal segmentation Plane 136 First Pavilion Main Facet 138 First Lower Girdle Facet 142 Second Pavilion 146 Second Pavilion Main Facet 148 Second Lower Girdle Facet

Claims (1)

A circular or polygonal girdle having an upper horizontal section surrounded by an upper outer periphery and a lower horizontal section surrounded by a lower outer periphery and parallel to the upper horizontal section;
A crown having a regular octagonal table facet on the horizontal horizontal section of the upper part of the girdle and having a substantially truncated polygonal pyramid formed upward from the girdle and forming the top surface of the truncated polygonal pyramid; ,
It is a diamond cut design with a pavilion with a polygonal pyramid with a bottom vertex formed below the girdle bottom horizontal section and facing downward from the girdle,
A straight line passing through the center of the table facet from the bottom vertex of the polygonal pyramid pavilion,
The plane that includes the Z axis and passes through each of the 8 vertices of the table facet is the first plane,
A straight line that passes through the point where one of the first planes intersects the outer periphery of the lower part of the girdle and is perpendicular to the Z axis,
The first plane perpendicular to the Z axis and the X axis passes through the point where the girdle lower outer periphery intersects, and the straight line perpendicular to the Z axis and the X axis is the Y axis.
When a plane that bisects an angle between two adjacent first planes including the Z axis is a second plane,
The crown has eight bezel facets, eight star facets and sixteen upper girdle facets along with the table facets,
Each bezel facet is a quadrilateral plane with the apex of the table facet and the point where the first plane passing through the apex intersects the girdle upper outer periphery, and the quadrilateral plane is the other two opposite vertices Each on the second plane next to each other and sharing one vertex of the other two paired vertices with the adjacent bezel facet;
Each star facet is an isosceles triangle formed by a vertex shared by two adjacent bezel facets with one side of the table facet as the base and both ends of the base as vertices,
Each upper girdle facet is a triangle formed by one side that intersects one end of the upper side of the girdle and one end of each side of the bezel facet, and a point where the second plane passing through the other end of the side intersects the outer periphery of the girdle upper side And
The pavilion consists of a first pavilion and a second pavilion separated by a horizontal cutting plane parallel to the lower horizontal section of the girdle,
The first pavilion has eight first pavilion main facets and sixteen first lower girdle facets,
Each first pavilion main facet is an isosceles triangle having a vertex at a point where the first plane intersects the outer periphery of the lower part of the girdle and having a base perpendicular to the first plane on the horizontal dividing plane,
Each first lower girdle facet has a girdle lower outer peripheral portion sandwiched between adjacent first and second planes, and a hypotenuse of an isosceles triangle of a first pavilion main facet having a vertex on the first plane. A quadrilateral plane surrounded by a side on the second plane passing through the end point on the second plane of the lower periphery of the lower part of the girdle and a side on the horizontal dividing plane passing through the base of the isosceles triangle ,
The second pavilion has 8 second pavilion main facets and 16 second lower girdle facets,
Each second pavilion main facet is a pentagonal plane symmetrical with respect to the first plane having a vertex at the bottom apex of the pavilion and sharing the base of the isosceles triangle of the first pavilion main facet, and the pentagonal planes are adjacent to each other. Has other vertices on each mating second plane, sharing the next second pavilion main facet with one side and two vertices,
Each second lower girdle facet has a vertex of a second pavilion main facet on a second plane, an end of the bottom side of the second pavilion main facet, and an edge of the second pavilion main facet having them as ends. A triangle formed by the side and the side on the horizontal dividing plane of the first lower girdle facet, and shares the side on the second plane with the adjacent second lower girdle facet.
And the first pavilion angle (p1) between the first pavilion main facet and the girdle lower section is 40-47 °,
In the graph in which the first pavilion angle (p1) is taken on the horizontal axis and the crown angle (c) between the bezel facet and the girdle lower horizontal section is taken on the vertical axis, (p1, c) is (40, 27.8) Crown angle (c) in a region sandwiched between a straight line connecting two points (47, 8.9) and a straight line connecting two points (40, 32.8) and (47, 15.0) (c )
In the graph in which the first pavilion angle (p1) is taken on the horizontal axis and the second pavilion angle (p2) between the second pavilion main facet and the girdle lower horizontal section is taken on the vertical axis, (p1, p2) is (40, 36.7) and (44, 37.0), a straight line connecting the two points, and (44, 37.0) and a straight line connecting the two points (47, 38.1), and (40 38.7) and a straight line connecting the two points (47, 41.3) and a second pavilion angle (p2) in a region sandwiched between the two points,
The X-axis coordinate (del) of the regular octagonal vertex of the table facet on the X-axis is 0.9 to 1.2 when the X-axis coordinate of the point where the outer periphery of the girdle crosses the X-axis is 2.0. Two-tier pavilion ornamental diamond.

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