WO2016083680A1 - Cut gem and article comprising such a gem - Google Patents

Abstract

The invention relates to a cut gem comprising a girdle (3) having four girdle sides (2) and four girdle corners (1), a table (4) realized by a flat facet, a crown (7) which extends between the table (4) and the girdle (3), in a first direction (H), and a pavilion (13) which extends in a second direction (B), opposite to said first direction (H), between said girdle (3) and a tip of the pavilion (14). The gem is noteworthy in that the crown (7) has 24 facets, the pavilion (13) has 32 facets and in that the four girdle sides (2) are identical in the form of an arc of a circle, the concavity of which is oriented towards the outside of the gem.

Description

 SIZED GEM AND ARTICLE COMPRISING SUCH A GEM

The invention relates to cut gems and articles comprising such gems.

 It also relates to improvements made to cut gems so that they have optical characteristics of light reflection greater than those obtained with a gem cut in accordance with a size called "princess", so that the brightness obtained is greater .

 The princess size of gems is widespread, and especially it is one of the sizes that gives the most brilliance to a diamond, just after the so-called "brilliant" size.

 US 8 181 482 discloses a gem whose size is made from a princess size, and which reminds the shape of a butterfly.

The cut gemstone described in this document includes:

 - a rondist with four sides of rondiste and four vertices of rondiste,

 a table made by a flat facet,

 - a crown that extends between the table and the rondiste, following a first direction,

 and a cylinder head which extends in a second direction opposite to said first direction, between said rounder and a bolt point.

The invention aims to provide a cut gem alternative, having a particularly bright sparkle.

 It proposes for this purpose a cut gem of the kind in question, which is remarkable in that the crown comprises twenty-four facets, the breech has thirty two facets and in that the four sides of rondiste are identical in the form of an arch. circle whose concavity is oriented towards the outside of the gem.

 Thus achieved, the gem exhibits a sharper luster than that obtained with a gem as described in US 8,181,482.

 According to the invention, the gemstone may also comprise the features presented below, taken separately or in combination.

Regarding the crown, it may include: o four table corner facets positioned at the four corners of the table,

 o four sides, each of the four sides of the crown comprising:

 - at least one break,

^■ a first crown star facet positioned between the cut-off and a first facet table corner, and

^■ a second crown star facet positioned between the cut and a second table corner facet.

 In the context of this embodiment, it may be provided that the twenty four facets of the crown have four side faces, four bezels, four cuts, eight star facets and four table corner facets.

 In addition, according to an embodiment which will be presented later, a particularly important brilliance is obtained with a cut gem in which:

 - the table is part of a table plan,

 - each bezel is part of a bezel plan,

 and wherein a bezel plane is inclined with respect to the table plane at an angle of substantially between 35 and 39 °.

Regarding the breech, it can include:

 o four flags,

 o a breech star with four breech-star facets connecting the breech point and the vertices of a girdle, and o at least three breech fences positioned on each side of each breech star facet, between a breech star facet and a flag among said four flags.

 As part of this embodiment, it may be provided that the thirty-two facets of the breech include four breechblocks, four breech-star facets and twenty-four breech fences.

In addition, according to an embodiment which will be presented later, a particularly important brilliance is obtained with a cut gem in which: - the table is part of a table plan,

 - each flag is part of a flag plan,

 and wherein each roof plane is inclined with respect to the table plane at an angle of substantially between 58 and 62 °.

For even better shine, the cut gemstone can be made with the following features:

 each of the rounder sides has a rounder side length which is the shortest distance taken between two adjacent roundel vertices,

 - said star of breech has a base of square section in the vicinity of the breech point,

 and wherein the square section base has a diagonal whose length is substantially between 5 and 11% of the rounder side length, preferably between 5.5 and 10.5%.

The cut gemstone may also include the following features:

 each of the rounder sides has a rounder side length which is the shortest distance taken between two adjacent roundel vertices,

 each of the rounder sides has a maximum depth, taken perpendicular to a line connecting the two adjacent vertices of rondiste,

 and wherein said maximum depth is substantially between 5.5 and 9.5% of said length of a rounder side.

In addition, the cut gemstone may further include the following features:

 each of the rounder sides has a rounder side length which is the shortest distance taken between two adjacent roundel vertices,

- the table has eight table vertices, of which four table vertices are also corners of table corners and four other vertices, alternating with the tops of table corners, also constitute vertices of cut,

 and wherein the distance between a cutoff vertex and the straight line connecting the two adjacent vertices of rondiste, perpendicular to said straight line, is substantially between 18 and 22% of said roundnesser side length.

 According to one embodiment of the invention, the gem is a diamond.

 The invention also relates to a jewelery article comprising at least one gem as defined above.

To be able to be executed, the invention is set forth in a sufficiently clear and complete manner in the following description which is, in addition, accompanied by drawings in which:

 FIG. 1 shows a gem according to an advantageous embodiment according to the invention, seen from above,

 FIG. 2 shows the gem represented in FIG. 1, seen from below,

 and FIG. 3 shows the gem illustrated in FIGS. 1 and 2, in side view.

In the following description, the terms "lower", "upper", "high", "low" etc. are used with reference to the drawings for greater ease of understanding. They should not be understood as limitations of the scope of the invention.

 The gem illustrated in Figures 1 to 3 is made from a princess cut diamond (that is to say a diamond whose general shape is similar to a pyramid whose base is square). However, it will be easy for the skilled person to achieve the particular size of stone that will now be described on other precious or semi-precious stones.

In the following description, reference will first be made to an upper part of the gem, that is to say the part of the gem that is usual to present towards the outside of a jewel when the gem is set on the jewel. This is the part of the gem visible directly by an observer. The upper part of the gennna has, in the usual way, a gem table formed by a flat facet and a crown, surrounding the table and formed of several contiguous facets. The ring extends substantially in a first direction H (see Figure 3).

 In contrast, the lower part of the gem facing the jewel will be called the gem's breech. The yoke extends in a direction B opposite to the direction H and will be described later with reference to FIG.

 Figure 1 shows a top view of a gem according to the invention, and therefore an upper part of the gem, whose general shape is substantially square.

 The widest part of the gem giving the diameter of the gemstone will be called the "girdle". The gem shown in the figures thus has a roughly square shaped girdle 3, which has four vertices 1 (hereinafter referred to as girdle vertices). between them by four sides 2 of equal length rondist.

 As can be seen in FIG. 1, each of the four sides 2 of the rondist is in the form of an arc of a circle (concave) whose concavity is turned towards the outside of the gem.

 FIG. 3 illustrates a side 2 of the girdle 3, the girdle 3 being schematically illustrated in broken lines between the two girdle vertices 1 in FIG.

 In the center of the upper part of the gem shown in Figure 1, is a table 4 octagonal. Four of the vertices of the octagonal table 4 align with the vertices of the girdler 1 along a diagonal D1 or D2 of the girdle, and constitute the corners 5 of the corner of the table. The other vertices of the table 4 alternate with the table corner vertices 5 and constitute vertex 6 of cut.

 Each of the two sides of the girdle 3 has a length L of the girdle side, which is the shortest distance taken between two adjacent girdle vertices 1.

The cutoff vertices 6 are each equidistant from two vertices 1 of adjacent rondist. The position of a cutoff vertex 6 is chosen on a line D4, which is perpendicular to the straight line D3 connecting the two vertices 1 of rondiste and which passes through the center C of the segment connecting the two vertices 1 of rondiste. The distance L1 between the center C and the cutoff vertex 6 is chosen such that it is substantially between 18 and 22% of the length L of the side 2 of the rounder.

 In the example illustrated in FIG. 1, the distance L1 between the center C and the cutoff vertex 6 corresponds to substantially 20% of the length L between two vertices 1 of the girdle.

 The depth L 2 of the concavities of the sides 2 of the girdle is also chosen according to the length L the shortest distance between two vertices 1 of the girdle (see FIG. 1).

 The depth L2 corresponds substantially between 5.5 and 9.5% of the length L of a side 2 of the rounder (see FIG. 1).

 Between the table 4 the sides 2 of the rounder 2 is formed the crown 7 of the gem (see FIGS. 1 and 3).

 The ring 7 comprises, in the example illustrated in the figures, four lateral faces 8 which correspond to the four faces along the profile of the curvature of the sides 2 of the girdle (see FIG. 3).

 At the four corners of the table 4, the ring 7 has four substantially diamond-shaped table corner facets 9, one of whose peaks is formed by a table top 5 and an opposite vertex is formed by a top 1 of the round. The other two vertices of the table corner facets 9 are referenced T in FIG.

 The crown also has four bezels 10 formed by facets defined between two adjacent vertices 1 of rondiste and two vertices T of the two facets 9 of adjacent table wedges associated with adjacent vertices 1 of rondiste and taken into consideration.

 The inclination of the bezels with respect to the plane of the table 4 is such that the plane P1 of the bezels is at an angle α with the plane P2 in which the table 4 is inscribed, the angle a being between 35 and 39 ° ( substantially 37 ° in the context of the example illustrated in Figure 3).

The crown 7 further comprises four facets called cuts 1 1, of triangular shape, located between the bezels and the table 4, and having for vertices two vertices 7 (in common with the bezels 10) and the vertex 6 of cut (in common with the table 4).

 Finally, between the four facets 9 of table wedge, the table 4 and the cuts 1 1, the crown comprises eight star facets 12, each of triangular shape, so called because they form a star around the table 4.

 Thus produced, the gem according to the invention and shown in the figures comprises a ring 7 which has twenty-four facets in total.

 Reference will now be made to the cylinder head of the gem according to the invention, with particular reference to FIG.

 The yoke 13 extends between the girdle 3 and a bolt 14 which it comprises. The girdle 3 being substantially square in shape, the yoke 13 has substantially the shape of a pyramid whose base is of square shape.

 The yoke 13 comprises a star 15 which has four branches connecting the bolt 14 and each vertex 1 of the rounder. The four branches of the breech star are called "breech star 16 facets".

 Each of the branches has a wide base 17 and a narrow peak-shaped vertex 18 which connects the girdle top. The wide bases 17 of the four breech-star-shaped facets 16 form the four abstract sides of a square (represented in dashed lines) whose center is made by the breech point.

14 (see Figure 2).

 In other words, in the vicinity of the bolt tip 14, the bolt star

15 has a base 19 of square section.

 According to a feature of a gem according to the invention, the base

19 has a diagonal 20 whose length is between 5 and 1 1% of the length L of the side of the rounder, preferably between 5.5 and 10.5%. In this example, the length of the diagonal 20 is substantially equal to 8% of the length L.

 In addition to the breech star 15, the breech 13 has four breechblocks 21 contiguous with the lateral faces 8.

Each breechblock 21 is formed by a flat facet with three sides: a first side 22 is curved and is common with one side of the face 8. A second and third sides 23 and 24 are of the same length and each of the second and third sides connects a girder vertex 1 to a point 25 on a line with the diagonal 20.

 The position of the point 25 on the line carrying the diagonal 20 is determined by the orientation of a plane P3 of the horn with respect to the plane P2 of table 4: according to the invention, the angle of inclination β of the plane P3 relative to the plane P2 is substantially 60 ° (more or less 2 ° - see Figure 3).

 Between a breech 21 and a breech star 16 facet, are provided three facets of breech fences 26.

 Each breech closing facet 26 is of triangular shape, with a base 27 which is carried by the straight line bearing the diagonal 20, and two sides connecting the base 27 to a rounder vertex 1.

 The three breech fences 26 thus have three bases 27 aligned along the line carrying the diagonal 20 and the point 25. Depending on the position of the breech closing facet 26, it also has a common side with a breech star facet 16, or with a breech 21 or no side in common if the breech closing facet 26 is between two other facets breech fence 26.

 In total, the yoke 13 comprises twenty-four facets breech fence 26, having a base 27 which is common to two facets breech fence 26 which are the image of each other by axial symmetry whose axis corresponds to the right bearing the diagonal 20.

 Thus, realized, the breech of the gem shown in the figures comprises thirty-two facets among which twenty-four facets breech fence 26, four pavilions 21, and four star-stud facets 16.

 The invention is not limited to the gem that has specifically been described. Furthermore, the invention extends to any jewelery article comprising at least one gem such as that particularly described and shown above.

Claims

 1. Cut Gemstone With  a girdle (3) having four sides (2) of a girdle and four vertices (1) of a girdle,  a table (4) made by a flat facet,  a crown (7) extending between the table (4) and the girdle (3), in a first direction (H),  - and a yoke (13) extending in a second direction (B) opposite said first direction (H), between said rounder (3) and a bolt (14), said gemstone being characterized in that the ring (7) has twenty-four facets, the yoke (13) has thirty-two facets and in that the four sides (2) of the rounder are identical in the shape of an arc of a circle whose concavity is oriented towards the outside of the gem. 2. Cut gem according to claim 1, wherein said ring (7) comprises:  o four table corner facets (9) positioned at the four corners of the table (4),  o four sides, each of the four sides of the crown comprising: ^■ at least one cut (1 1), ^■ a first star facet (12) positioned between the crown break (1 1) and a first side corner of the table (9), and ^■ a second crown star (12) facet positioned between the cut (1 1) and a second table corner facet (9). The cut gem according to claim 2, wherein the twenty-four facets of the crown (7) comprise four lateral faces (8), four bezels (10), four cuts (11), eight star facets (12) and four facets of table wedge (9). The cut gem according to claim 3, wherein:  the table (4) is part of a table plan (P2),  each bezel (10) is inscribed in a bezel plane (P1), and wherein a bezel plane (P1) is inclined with respect to the table plane (P2) at an angle (a) substantially between 35 and 39 °. 5. A gem according to any one of claims 1 to 4, wherein said yoke (13) comprises:  o four flags (21),  a breech star (15) having four yoke star facets (16) connecting the breech tip (14) and the vertices (1) of the girdle (3), and  o at least three breech fences (26) positioned on each side of each breech star facet (16), between a star-shaped star facet (16) and a flag (21) of said four flags (21). A cut gem according to claim 5, wherein the thirty-two facets of the yoke (13) comprise four yoke bolts (21), four yoke star facets (16) and twenty four yoke fences (26). The cut gem according to any one of claims 5 or 6, wherein:  the table (4) is part of a table plan (P2),  - each pavilion (21) is part of a pavilion plan (P3) and wherein each horn plane (P3) is inclined with respect to the table plane (P2) at an angle (β) of substantially between 58 and 62 °. 8. Cut gem according to any one of claims 5 to 7, wherein: each of the rounder sides (2) has a rounder side length (L) which is the shortest distance taken between two adjacent rounder vertices (1),  said breech star (15) has a base (19) of square section in the vicinity of the breech point (14), and wherein the square section base (19) has a diagonal (20) whose length is between substantially 5 and 1 1% of the rounder length (L). The cut gem according to any one of the preceding claims, wherein:  each of the rounder sides (2) has a rounder side length (L) which is the shortest distance taken between two adjacent rounder vertices (1),  - Each of the sides (2) of the rounder has a maximum depth (L2), taken perpendicularly to a straight line connecting the two adjacent vertices (1) of the rondist, and wherein said maximum depth (L2) is substantially between 5.5 and 9.5% of said length (L) of a girder side. The cut gem according to any one of the preceding claims, wherein:  each of the rounder sides (2) has a rounder side length (L) which is the shortest distance taken between two adjacent rounder vertices (1),  the table (4) has eight table tops (5, 6), among which four table tops also constitute table wedges (5) and four other vertices, alternating with the corners of the table corners (5) , also constitute cutting vertices (6), and wherein the distance (L1) taken between a cutoff vertex (6) and the straight line connecting the two adjacent vertices (1) of the rondist, perpendicularly to said straight line, is substantially between 18 and 22% of said length (L) side (2) of the rounder. 1 1. A cut gem according to any one of the preceding claims, the gem being a diamond. 12. Jewelery article comprising at least one gem according to any one of the preceding claims.