WO2020008454A1

WO2020008454A1 - Cross-oriented method for cutting and polishing gemstones

Info

Publication number: WO2020008454A1
Application number: PCT/IL2019/050726
Authority: WO
Inventors: Uri Peleg
Original assignee: AVLAS, Menahem
Priority date: 2018-07-02
Filing date: 2019-07-01
Publication date: 2020-01-09

Abstract

A brilliant-cut gemstone (such as a diamond) comprising a crown, a girdle, and a pavilion having from 4 to 32 facets, wherein the pavilion includes four main pavilion facets which are perpendicular to each other, all together forming a cross shape, each main pavilion facet is polished as a rectangular bar, ending in a triangle form, such that that triangle of each bar intersects with the triangles of all other bars at the central axis of the pavilion, to thereby form a pavilion tip.

Description

CROSS-ORIENTED METHOD FOR CUTTING AND POLISHING

GEMSTONES

Field of the Invention

The present invention relates to the field of gemstone construction. More specifically, the invention is related to construction of a brilliant-cut diamond to provide improved cross-effect.

Background of the Invention

There are three basic sections to a round brilliant-cut diamond: the crown the girdle and the pavilion, where the girdle which is the narrow rim of the gemstone that separates the crown from the pavilion, and is left in an unpolished state with a matte finish or sometimes, is being round. The largest flat top facet of the crown is the table.

Brilliance is the most important feature, which is a measure how much it shines. When light rays are incident on table and reach the pavilion, most of the rays are reflected inward again and escape upon reaching the crown to reach the observer's eyes as brilliance. The angle of the pavilion influences the total reflection and is important to the brilliance of the diamond.

Scintillation is the glittering of the reflected light of a diamond caused by the movement of either the observer or the diamond itself and greatly depends on the size of the diamond, the number of facets, the polish of the facets, and the accuracy of the angles of the respective facets.

A good cut determines the appearance (brilliance, dispersion, and scintillation) of the diamond. The round brilliant-cut diamond is characterized by many facets of different shapes and sizes. This maximizes a diamond's brilliance by minimizing the amount of light that can escape through the pavilion, as well as maximizing the scintillation effect of the crown by increasing and varying the reflective surfaces. The typical brilliant cut has 58 total facets and may fit the "Ideal Cut", a range of proportions and angles that are maintained as a standard by the American Gem Society.

The brilliance of the brilliant-cut diamond has been increased by exceeding the typical 58 facets. The increased number of facets in the pavilion and the different angles at which a great many of them are cut result in enhanced brilliance. However, these attempts caused the diamond to be taller, and therefore, a raw diamond with a given volume yielded in less polished diamonds.

Some of the raw diamonds are mined in the form of two base-to-base pyramids. Generally, such raw diamonds are first polished to have essentially round base. Then the mutual base is cut to separate between the base-to-base pyramids. However, prior art polishing methods generally include polishing of 8 main facets to get a desired brilliance level, and therefore, more diamond material is lost.

A major part of the world population includes Cristian women. In year 2015, the world population included 2.5 billion people, at least a half of which are women, who are the major consumers of diamonds and other gemstones, which are embedded in jewels. Many of the Cristian women have religious excitement to icons and symbols which are in the form of a cross, since the cross has deep Cristian religious meaning. Therefore, it would be desired to add a cross brilliance effect to diamonds and other gemstones. All the methods described above have not yet provided satisfactory solutions to the problem of polishing the pavilion of diamonds with high yield and high quality and also failed to provide cross brilliance effect to diamonds and other gemstones.

It is an object of the present invention to provide a new and unique brilliant polishing the pavilion of diamonds and other gemstones with high yield, while maintaining the features of cross brilliance effect, bigger dispersion, and scintillation of a gemstone.

Other objects and advantages of the invention will become apparent as the description proceeds.

Summary of the Invention

A brilliant-cut gemstone (such as a diamond) comprising a crown, a girdle, and a pavilion having from 4 to 32 facets, wherein the pavilion includes four main pavilion facets which are perpendicular to each other, all together forming a cross shape, each main pavilion facet is polished as a rectangular bar or another elongated bar, ending in a triangle form, such that that triangle of each bar intersects with the triangles of all other bars at the central axis of the pavilion, to thereby form a pavilion tip. The brilliant-cut gemstone may further comprise 2-6 lower griddle facets, formed between each pair of main pavilion facets and arranged in mirrored pairs, each having a rectangular bar shape, which enhance light reflection and project a decorative corona around each cross bar. The angle of each main pavilion facet (with respect to the table) may be in the range of 38-42°. The angle of a first pair of lower griddle facets (with respect to the table) may be in the range of 40-46°. The angle of a second pair of lower griddle facets (with respect to the table) may be in the range of 40- 48°. The angle of a third pair of lower griddle facets (with respect to the table) may be in the range of 40-50°. Each of the four main pavilion facets may have an additional inclined facet and between each pair of main pavilion facets, there are also five lower griddle facets, arranged in two mirrored pairs and one mutual facet, each having a triangular shape, which enhance light reflection and project a decorative corona around each cross bar, where the angle of each main pavilion facet (with respect to the table) may be in the range of 38-42°; the angle of the lower griddle facets in the range of 50-60°; the angle of lower griddle facets (with respect to the table) may be in the range of 38-53°; the angle of lower griddle facets (with respect to the table) may be in the range of 38-55°.

The cross bars may be polished to have a trapezoid-like shape, which extends outwardly.

The the main pavilion facets which are perpendicular to each other, all together may form a PLUS (+) shape.

Brief Description of the Drawings

The above and other characteristics and advantages of the invention will be better understood through the following illustrative and non-limitative detailed description of preferred embodiments thereof, with reference to the appended drawings, wherein:

Fig. la (prior art) is a side view of a typical brilliant diamond, which comprises a crown, a griddle and a pavilion;

Fig. lb (prior art) is a top view of a typical brilliant diamond;

Fig. lc (prior art) is a bottom view of a typical brilliant diamond; Fig. 2a is a bottom view of the pavilion of the brilliant diamond, according to a preferred embodiment of the invention; Fig. 2b is a side view of the pavilion of the brilliant diamond, according to a preferred embodiment of the invention;

Fig. 2c is a top view of the crown of the brilliant diamond, which is identical to a conventional crown;

Figs. 3a-3c illustrate another design of a square diamond with cross shaped polishing of the brilliant diamond, according to a preferred embodiment of the invention;

Figs. 4a-4c illustrate another design of a square diamond with cross shaped polishing of the brilliant diamond, according to a preferred embodiment of the invention; and

Figs. 5a-5b illustrate another design of a square diamond with cross shaped polishing of the brilliant diamond, according to a preferred embodiment of the invention.

Detailed Description of Preferred Embodiments

The present invention proposes unique brilliant cut and polishing of the pavilion of diamonds and other gemstones with high yield, while maintaining the features of cross brilliance effect, greater dispersion, and scintillation of a gemstone.

In the unique brilliant polishing of the pavilion, the number of pavilion main facets is decreased from the typical number of 8 main facets to be 4 pavilion main facets, thereby reducing the polished diamond volume and increasing the yield, while maintaining the brilliance, dispersion, and scintillation of the diamond. Thus, diamonds with these properties have the advantage of lower height, while maintaining high level of brilliance, scintillation, and bigger dispersion caused by the unique brilliant cut and polishing of the pavilion, proposed by the present invention.

Fig. la (prior art) is a side view of a typical brilliant diamond, which comprises a crown, a griddle and a pavilion. The typical crown has a total of 33 facets (including the table): 8 star facets, 8 kite-shaped facets and 16 upper-girdle facets. Although this example has a girdle of only one facet, other embodiments may have girdles with multiple facets. A culet, which is a flat face on the bottom of a gemstone, may optionally be added to protect the integrity of the gemstone (to protect from potential damages caused by the fragility of the pointed tip of the pavilion).

Fig. lb (prior art) is a top view of a typical brilliant diamond, showing a typical crown that has a total number of 33 facets (including the table): 8 star facets, 8 kite-shaped facets and 16 upper-girdle facets.

Fig. lc (prior art) is a bottom view of a typical brilliant diamond, showing a typical pavilion that has a total number of 25 facets (including the culet): 16 lower griddle facets, 8 pavilion main facets and an optional culet.

Fig. 2a is a bottom view of the pavilion of the brilliant-cut diamond, according to a preferred embodiment of the invention. It can be seen that there are four main pavilion facets 1-4, which (in this example) are perpendicular to each other, all together forming a cross shape. Each main pavilion facet is polished as a rectangular bar, ending in a triangle form, such that that triangle of each bar intersects with the triangles of all other main pavilion facet bars at the central axis of the pavilion 100, to thereby form a pavilion tip. Between each pair of main pavilion facets, there are also six lower griddle facets 6-11 (arranged in mirrored pairs [6;7], [8;9] and [10; 11]) each having a rectangular bar shape, which enhance light reflection and project a decorative corona around each cross bar (it should be noted that similarly to the six lower griddle facets 6-11 between main pavilion facets 1 and 2, there are also six lower griddle facets between the other adjacent pairs of main pavilion facets 1 and 4, 2 and 3, 3 and 4). In this example, the angle of each main pavilion facet (with respect to the table) is in the range of 38-42°. The angle of lower griddle facets 6-7 (with respect to the table) is in the range of 40-46°. The angle of lower griddle facets 8-9 (with respect to the table) is in the range of 40-48°. The angle of lower griddle facets 10-11 (with respect to the table) is in the range of 40- 50°.

Fig. 2b is a side view of the pavilion of the brilliant diamond, according to a preferred embodiment of the invention. The figure shows two main pavilion facets 1-2 and six lower griddle facets 6-11 from the direction that coincides with the center line between the mirrored pairs [6;7], [8;9] and [10; 11]. Fig. 2c is a top view of the crown of the brilliant diamond, which is identical to a conventional crown.

Figs. 3a-3c illustrate another design of a square diamond with cross shaped polishing of the brilliant diamond, according to a preferred embodiment of the invention. Figs. 3a-3b are top and side views, respectively. Fig. 3b shows two main pavilion facets 1-2 and five lower griddle facets (arranged in two mirrored triangular shaped pairs 15-16, 23-24, and one mutual facet 6).

Fig. 3c shows a bottom view, where each of the four main pavilion facets 1- 4 has an additional inclined facet 25-28, respectively. Between each pair of main pavilion facets (for example, facets 1-2), there are also five lower griddle facets (arranged in two mirrored pairs 15-16, 23-24, and one mutual facet 6) each having a triangular shape, which enhance light reflection and project a decorative corona around each cross bar. The same applies to facets 1-3 that have five lower griddle facets (arranged in two mirrored pairs 9-10, 17-18, and one mutual facet 5), to facets 2-4 that have five lower griddle facets (arranged in two mirrored pairs 13-14, 21-22, and one mutual facet 7), to facets 3-4 that have five lower griddle facets (arranged in two mirrored pairs 11-12, 19-20, and one mutual facet 8). In this example, the angle of each main pavilion facet (with respect to the table) 1-4 is in the range of 38-42°. The angle of lower griddle facets 5-8 (with respect to the table) is in the range of 50-60°. The angle of lower griddle facets 9-16 (with respect to the table) is in the range of 38-53°. The angle of lower griddle facets 17-24 and 25-28 (with respect to the table) is in the range of 38-55°.

Figs. 4a-4c illustrate another design of a square diamond with cross shaped polishing of the brilliant diamond, according to a preferred embodiment of the invention. It can be seen from Fig. 4c that there are four main pavilion facets 1-4, which (in this example) are perpendicular to each other, all together forming a cross shape. Here also, each main pavilion facet is polished as a rectangular bar, ending in a triangle form, such that that triangle of each bar intersects with the triangles of all other main pavilion facet bars at the central axis of the pavilion 100, to thereby form a pavilion tip. Between each pair of main pavilion facets, there are also four lower griddle facets 6-9 (arranged in mirrored pairs [6;7] and [8;9] and one mutual facet 40) each having a rectangular bar shape, which enhance light reflection and project a decorative corona around each cross bar (it should be noted that similarly to the four lower griddle facets 6-9 between main pavilion facets 1 and 2, there are also four lower griddle facets between the other adjacent pairs of main pavilion facets 1 and 4, 2 and 3, 3 and 4).

Figs. 5a-5b illustrate another design of a square diamond with cross shaped polishing of the brilliant diamond, according to a preferred embodiment of the invention. It can be seen from Fig. 5c that there are four main pavilion facets 1-4, which (in this example) are perpendicular to each other, all together forming a cross shape. Here also, each main pavilion facet is polished as a trapezoid-like bar, ending in a triangle form, such that that triangle of each trapezoid-like bar intersects with the triangles of all other main pavilion facet bars at the central axis of the pavilion 100, to thereby form a pavilion tip. Between each pair of main pavilion facets, there are also four lower griddle facets 6-9 (arranged in mirrored pairs [6; 7] and [8;9] and one mutual facet 50) each having a converging quadrangle shape, which enhance light reflection and project a decorative corona around each cross bar (it should be noted that similarly to the four lower griddle facets 6-9 between main pavilion facets 1 and 2, there are also four lower griddle facets between the other adjacent pairs of main pavilion facets 1 and 4, 2 and 3, 3 and 4). In this design, the cross bars are polished to have a trapezoid-like shape, which extends outwardly. This adds a new cross brilliance effect, which is reflected via the table, along with a corona that is created by the polished lower griddle facets.

These features are extremely important when the diamond is embedded into jewelry, such as a ring. Using larger gemstone provides more impressive appearance to the jewel. In addition, since the diamond has a lower profile, a raw diamond with a given volume will have higher yield of cut and polished diamonds.

It should be noted that even though all the examples above were directed to cross-effect which sometimes has religious meaning, the proposed brilliant cut and polishing of the pavilion of diamonds and other gemstones, the invention is also meant to include pure decorative effect, such as a‘PLUS’ effect (a‘+’ effect) without any particular religious meaning (rather than cross-effect). The above examples and description have of course been provided only for the purpose of illustration, and are not intended to limit the invention in any way. As will be appreciated by the skilled person, the invention can be carried out in a great variety of ways, employing more than one technique from those described above, all without exceeding the scope of the invention.

Claims

1. A brilliant-cut gemstone comprising a crown, a girdle, and a pavilion having from 4 to 32 facets, wherein said pavilion includes four main pavilion facets which are perpendicular to each other, all together forming a cross shape, each main pavilion facet is polished as an elongated or rectangular bar, ending in a triangle form, such that that triangle of each bar intersects with the triangles of all other bars at the central axis of the pavilion, to thereby form a pavilion tip.

2. A brilliant-cut gemstone according to claim 1, further comprising 2- 6 lower griddle facets, formed between each pair of main pavilion facets and arranged in mirrored pairs, each having a rectangular bar shape, which enhance light reflection and project a decorative corona around each cross bar.

3. A brilliant-cut gemstone according to claim 1, in which:

a) the angle of each main pavilion facet with respect to the table is in the range of 38-42°;

b) the angle of a first pair of lower griddle facets with respect to the table is in the range of 40-46°;

c) the angle of a second pair of lower griddle facets with respect to the table is in the range of 40-48°;

d) the angle of a third pair of lower griddle facets with respect to the table is in the range of 40-50°.

4. A brilliant-cut gemstone according to claim 1, in which each of the four main pavilion facets has an additional inclined facet and between each pair of main pavilion facets, there are also five lower griddle facets, arranged in two mirrored pairs and one mutual facet, each having a triangular shape, which enhance light reflection and project a decorative corona around each cross bar wherein:

b) the angle of the lower griddle facets in the range of 50-60°;

c) the angle of lower griddle facets with respect to the table is in the range of 38-53°;

d) the angle of lower griddle facets with respect to the table is in the range of 38-55°.

5. A brilliant-cut gemstone according to claim 1, in which the cross bars are polished to have a trapezoid-like shape, which extends outwardly.

6. The gemstone as recited in claim 1, wherein the brilliant-cut gemstone is a diamond.

7. The gemstone as recited in claim 1, wherein the main pavilion facets which are perpendicular to each other, all together form a PLUS shape.