The invention relates to a field of gemstones and more specifically to princess cut and cushion cut gemstones, where in such gemstone encompasses the shape of a heart within the body of the gemstone, and the method of manufacture of the same.
A diamond quality is usually assessed by its carat value, color, clarity, cut and shape. In addition to these attributes, a diamond's quality is assessed by its symmetry and reflective quality, which is a result of a diamond's cut which affects and potentially enhances all the mentioned characteristics. The cut on the facets determines how well a diamond “performs,” in other words, how well it reflects light under a variety of lighting conditions and situations, and more importantly how they perform in more natural lighting situations. Practically any stone will look impressive under the bright spotlights of a jewellery store, but a rare few have the unique combination of precise cut, shape, and angles to hold their brilliance in natural lightening conditions.
The sophistication of diamond cutting is reaching new zeniths each time, with computerized machinery and laser technology also being used for diamond cutting and hence there are challenges to bring in newer innovations, in respect of cuts, appearance and shapes, that give a novel effect, which are a result of innovative cutting. There is a great deal of precision in cutting and polishing called for in order to achieve the maximized light return through the top of the diamond, which decides the brilliance and sparkle of the diamond. Many of the processes above are thus mechanical and driven by algorithms.
U.S. Pat. No. 8,156,760 discloses an invention that has 162 facets such that the crown has 65 separate facets and the pavilion has 97 separate facets.
U.S. Pat. No. 8,813,519 B2 discloses a modified princess cut diamond and a method of forming a modified princess cut diamond into a symmetrical shape possessing a radiating heart and arrows pattern characteristic of the true hearts and arrows pattern in a round cut diamond.
However the invention disclosed in the afore referred patent does not reveal or disclose an invention, where in the gemstone would give the effect of a heart within a princess cut, or cushion cut gemstone, and make it appears as if a shaped gem is inset within another gemstone.
This invention discloses for the first time, a series of facet cuts by which a heart shape design can be seen within a princess cut or cushion cut gemstone, from the pavilion (Bottom side) and the Crown (Top side). Because of the specific facet cuts at specific angles and specific depths around the pavilion surface, it gives the appearance of a gemstone within another gemstone. These facet cuts at specific girdle depths produce the visual effect of a Heart Shape diamond inside a princess cut or cushion cut gemstone.
In its main aspect the invention relates to gemstones, which are symmetrical in shape, and visually encompasses a heart shape within and the method of manufacturing the same. This has been made possible by the specially conceived cuts on the various facets of the diamond, at specific angles to each other and at specific depths.
The gemstone disclosed in this invention comprises (a) an upper table facet (b) a lower pavilion with a culet and pavilion facets comprising of triangoid facets, chevron facets and 4-sided pavilion main facets, all in the ratio of x: 4x:2x, where is x is ≥4, and cut as specific triangle main angles and chevron angles. The pavilion facets are arranged on either side of an axis line which traverses the pavilion along a horizontal plane. Each of the pavilion facets have a corresponding symmetrical pair on the other side of the axis line. The chevron facets further comprise of equal number of substantially triangular pavilion lower half facets and pavilion lower half corner facets. At least one vertice of each of the afore mentioned facets point towards the culet (C) a girdle with girdle main facets separates and distinguishes the table facet from the pavilion.
The short sides of each pavilion main facet, which are preferably kite shaped, converge at the culet, and the long sides of this facet converge at 1st points at a girdle depth in the range of 70 to 86%. The short sides and long sides of the pavilion main facets converge at 2nd points at a girdle depth varying from 88% to 96%;
Pairs of pavilion short half facets are faceted out of the culet end side of the chevron facets at the girdle depth of 1st point, along a cable connecting the 1st points, at 1st pavilion short half angles such angles being 15° to 30° less than the triangle main angle, and 2° to 9° less than the chevron angles. The cable intersects the interphase of the pairs of pavilion short half facet. The pairs of pavilion short half facets, alternate the long sides of the pavilion main facets. The 2nd common interphase of each facet of the pavilion main facets and the adjacent pavilion short half facets are at an angular variance of 0.05° to 9.0°, and the angle of variance along the interphase of the short sides of adjacent pavilion main facets is in the range of 0.05° to 9°;
The 1st pavilion short half angles of alternate pairs of chevron facets, vary in the range of 0.05° to 9°. The pavilion main facets are further chiselled at the girdle depth of the 2nd point and the angle so formed is 0.25° to 8° less than 1st pavilion short half angles and referred to as 2nd pavilion short lower half angles. Further the girdle depth of the 1st point of one pair of symmetrical pavilion main facets is 0.5% to 10% less than the girdle depth of the 1st point of other pavilion main facets. The precision of the above, is required to obtain the shape of the heart within the gemstone.
In another aspect, the gemstone may be of a princess cut or a cushion cut having all the features of the pavilion as mentioned above, and the table facet may comprise of a single crown or a double crown
In yet another aspect of the invention, the gemstone has 4 to 12 pavilion main facets and 4 to 12 pavilion lower half facets and 4 to 12 pavilion lower half corner facets and 8 to 24 pavilion short half facets.
In a further aspect, the 1st pavilion short half angle of each of the pairs of pavilion short half is at a variance of 0.20° to 2.0° with the 1st pavilion short half angle of the adjacent pair of pavilion short half facets and the corresponding 2nd pavilion short half angle may vary in the range of 0.05 to 4.0°, or could even be a fixed value.
In an ideal aspect of the invention, the pavilion in the gemstone has 8 pavilion main facet and 8 pavilion lower half facets and 8 pavilion lower half corner facets and 16 pavilion short half facets and the girdle depth at the 1st point ranges from 80-86%, and the girdle depth at the 2nd point ranges from 88.5 to 91%. The chevron angles of pavilion lower half corner facets are 0.05° to 2.0° greater than the chevron angle of the pavilion lower half facets, and the angle of variance between adjacent pavilion short half facets and chevron facets, and adjacent pavilion main facets are as mentioned above. Further the 1st pavilion short half angle of each of the pairs of pavilion short half facets is at a variance of 0.20° to 2.0° with the pavilion short half angle of the adjacent pair of pavilion short half facets and the 2nd pavilion short lower half angle is fixed. In addition the adjacent pavilion short half facets along its common interphase are at an angular variance of 0.20° to 6.0° and the angle of variance between the interphase of the short sides of adjacent pavilion main facets is in the range of 0.05° to 4.5°.
In an interesting aspect of the invention, in addition to all the features mentioned above, a pair of symmetrical small triangular pavilion short half facets, having a common side along the axis line, have sides opposite the vertex converge at a point which is at a girdle depth approximately midway between the girdle depth of 1st point and the 2nd point of pavilion main facets nesting the small pavilion short half facets. Further, a second pair of symmetrical short half facets also having one common side along the same axis line, has a second common vertex at a common point on the cable and axis line. The second common vertex is at a girdle depth approximately equivalent to the girdle depth of the longest pavilion main facet. The girdle depths of the 1st points and the points intercepting the cable along the interphase of the short half facets are in specific relation to the girdle depth of the longest pavilion main facet. The features in combination gives a true heart shape, within the symmetrically cut gemstone.
The above features of the invention is best seen in a gemstone with a high refractive index such as a diamond, where with the above facets, one is able to visually see a heart shape within the gemstone. The gemstone may be of a princess cut or a cushion cut.
In its main embodiment the invention describes a symmetrically cut gemstone, preferably of princess cut or cushion cut, which visually encompasses a heart shape within. (
The princess cut and cushion cut gemstone as described in this invention can have a upper crown table facet comprising of a single crown or double crown.
In case of a princess cut gemstone with a double crown table facet, as seen in
In case of a cushion cut gemstone, with a double crown, as seen in
The crown angles on the Upper double crown table are at recommended angles as seen in
No claim is being made exclusively in respect of the crown angles or the crown table, but only in its novel combination with the pavilion as described in this invention.
As seen in
In the gemstone of the present invention, the triangle main angle (W), i.e the angle formed by the girdle and the triangoid facets, is in the range of 55° to 65°, and the chevron angle i.e the angle formed by the triangle main facet with the chevron facets is in the range of 35° to 45° as seen in
The Triangoid facets (L), the chevron facets (M, N) and the pavilion main facets (O) are in the ratio of x: 4x:2x, where X is ≥4 and an even number. The chevron facets comprise of pavilion lower half corner facets (N) and substantially triangular pavilion lower half facets (M). The adjacent pairs of pavilion lower half corner facets (N) are symmetrical. The pairs of pavilion lower half facets alternate pairs of pavilion lower half corner facets.
In a princess cut gemstone, (
In a cushion cut gemstone, (
As seen in
Pairs of pavilion short half facets are nested between the long sides of the pavilion main facets (O). The pavilion short half facets (T), are faceted out of the culet end side of chevron facets (M,N), at 1st pavilion angles around the depth of the 1st point along a cable (RR) joining the 1st points (R). The angle formed by the pavilion short half facets and the remaining chevron facet is referred to as the 1st pavilion short half angle. (Y). The 1st pavilion angles are formed around the pavilion at a girdle depth of the 1st point forming the cable (RR). The pairs of pavilion short half facets have a common side, referred to as the 1st common interphase, which is continuous with the common side of the corresponding pairs of chevron facets. The 1st common interphase, separating the adjacent pairs of pavilion short half facets intersects the cable (RR) at R′. Two pairs of pavilion short half facets have a common side along the axis line.
One of the pairs of symmetrical short half facets having one common side along the axis line, has a second common vertex (V′) at a common point on the cable (RR) and axis line at a girdle depth approximately equivalent to the girdle depth of the longest pavilion main facet (O). In order to obtain the shape of a heart, it is recommended that the variance in girdle depth of V′ be within 15% of the recommended girdle depth. (
The 1st pavilion short half angle is 15° to 30° less than the Triangle main angle (W), and 2° to 9° less than the chevron angles (X,X1). The 1st pavilion short half angles (Y) corresponding to alternate pairs of chevron facets vary from 0.05° to 9° in the outer limit; (
In a princess cut gemstone, the 1st pavilion short half angles (Y) corresponding to pairs of pavilion lower half facets is less than that of pavilion lower half corner facets by 0.05° to 5.0°.
In a cushion cut gemstone, the 1st pavilion short half angles (Y) corresponding to pavilion lower half facets are less than that of the pavilion lower half corner facets by 0.05° to 5.0°. Further the 1st pavilion short half angle (Y) of each of the lower half facets and the lower half corner facet are in variance with its corresponding adjacent facet in the range of 0° to 0.1
In a workable embodiment, the pavilion of the gemstone comprises of 4 to 12 pavilion main facets (O) and 4 to 12 pavilion lower half facets (M) and 4 to 12 pavilion lower half corner facets (.N) and 8 to 24 pavilion short half facets (T) and the girdle depth at the 1st point ranges from 80-84.5%, and the facet depth at the 2nd point ranges from 88.5 to 91%.
In an improved embodiment of this invention, in respect of the princess cut and cushion cut gemstone, the 1st pavilion short half angle (Y) of each of the pairs of pavilion short half facets (T) is at a variance of 0.20° to 2.0° with the 1st pavilion short half angle (T) of the adjacent pair of pavilion short half facets and the variation in the corresponding 2nd pavilion short lower half angles (Z) is in the range of 0.05° to 4.0°. In another embodiment of this invention, the 2nd pavilion short lower half angles. (Z) remain the same in all pavilion main facets.
In a precise embodiment of this invention as described above, the gemstone of princess cut has 8 pavilion main facets (O1 to O8) and 8 pavilion lower half facets (M1 to M8) and 8 pavilion lower half corner facets (N1 to N8)) and 16 pavilion short half facets (T1 to T16). The pairs of pavilion short half facets with a common side along the axis line are T1, T16, and T8, T9. The small pavilion short half facets are T1, T16, and are nested between pavilion main facets O4 and O5. (
In a precise embodiment of this invention as described above, the gemstone of cushion cut has 8 pavilion main facets (O1 to O8) and 8 pavilion lower half facets (M1 to M8) and 8 pavilion lower half corner facets (N1 to N8)) and 16 pavilion short half facets (T1 to T16). The pairs of pavilion short half facets with a common side along the axis line are T1, T16, and T8, T9. The small pavilion short half facets are T1, T16, and are nested between pavilion main facets O4 and O5. (
The suggested girdle depths in order to obtain a design of the heart within the gemstone, both cushion and princess cut is in relation to the the girdle depth of the 1st point of the pavilion main facet with the longest arms represented by R1, which is 80% of the girdle depth of the gemstone. The subsequent 1st points of the pavilion main facets as represented by R2, R3, R4, R5, R6, R7, and R8 are at a depth of 1.05 R1, 1.04 R1, 1.04 R1, 1.05 R1, R1, 1.07 R1 and 1.07 R1. The girdle depth at which the common interphase between pairs of short half facets intersect the cable (RR) as represented by R′1, R′2, V1, R′4, R′5, R′6, and R′8 are at 1.03 R1, 1.05 R1, 1.03 R1, 1.04 R1, 1.03 R1, 1.01 R1, 1.07 R1 and 1.01 R1.
The sharpness of the shape of the heart within the gemstone is obtained by minimising the angular difference between the 1st pavilion short half angles and the 2nd pavilion short lower half angles.
In a commercially attractive embodiment of this invention in respect of princess cut and cushion cut gemstones, the 2nd pair of pavilion short half facets having a common side along the axis line, at the azimuth angle of approximately 60° to 220°, are smaller than the remaining pavilion short half facets. The sides (U) opposite to the vertex of these small pavilion short half facets, converge at a point (V) along the common axis line, which is midway between the girdle depth of the 1st point and 2nd point of the pavilion main facets, nesting these small pavilion short half facets. This creates the indent to give a perfect shape of the heart when the gemstone is seen from the pavilion view or the table view. (
The suggested girdle depths in order to create a heart shape design with an indent is in relation to the girdle depth of the 1st point of the pavilion main facet with the longest arms represented by R1, which is at 80% of the girdle depth and the subsequent 1st points of the pavilion main facets as represented by R2, R3, R4, R5, R6, R7, and R8 are at a depth of 1.05 R1, 1.04 R1, 1.04 R1, 1.05 R1, R1, 1.07 R1 and 1.07 R1. The the girdle depth at which the common interphase (P′) between pairs of short half facets intersect the cable (RR) as represented by R′1, R′2, V1, R′4, R′5, R′6, and R′8 are at 1.03 R1, 1.05 R1, R1, 1.04 R1, 1.03 R1, 1.01 R1, and 1.01 R1.
Table 2 below gives the percentage depth of the pavilion main facets, pavilion lower half facets, pavilion lower half corner facets and pavilion short half facets, the 1st pavilion short half angle and the 2nd pavilion short lower half angle with reference to the girdle, where girdle is considered as 0 and culet as 100.
At
Table 3 below gives the azimuth index range at which the pavilion main facets, pavilion lower half facets, pavilion lower half corner facets and pavilion short half facets, the 1st pavilion short half angles and the 2nd pavilion short lower half angles are around the gemstone.
Table 4 gives the range of angle variation between the chevron facets, the pavilion short half facets and pavilion main facets at which it is possible to obtain a heart shape within the gemstone.
In another main embodiment for manufacture of the symmetrically cut gemstone, visually encompassing a heart shape (Z1) within, a gemstone of princess cut or cushion cut is obtained by a process known in the art. A symmetrically shaped princess cut or cushion cut gemstone has an upper table facet (A), a girdle (B) which separates and distinguishes the table facet (A) from a lower pavilion (C), which is cone shaped. The tip of the cone is referred to as the culet (D). Cutting and polishing of the table facets and the pavilion facets both contribute to obtaining optimum lustre, radiance and brilliance in a gemstone like a diamond.
The upper table facet may consist of a single crown or a double crown. In case of a double crown in a princess cut gemstone, the upper table facet of the gemstone is cut chiseled and polished to form a central table facet (A1), surrounded by a plurality of crown-1 facets (E), and an equal number of crown-2 facets, (F), crown corner facets (G) and star corner facets (H) and double the number of star angle facets (.I) and crown upper angle facets (J). In a preferred embodiment of the invention, as seen at
In case of a cushion cut gemstone, with a double crown, as seen in
The crown angles are determined by viewing the gemstone from a side profile and visually estimating the angle of the top portion of the gemstone. The upper crown-1 angle cut is in the range of 38° to 52°, and the respective azimuth angle of the 4 side facets are 0°, 90°, 180° and 270° respectively. At the same azimuth angle, the Crown-2 facets are at an angle in the range of 25° to 40°. Crown 2 facets are optional. Crown 2 facets add more brightness to the stone. The star angle facets and the star corner facets are placed in the corner at 18° to 20° of all four sides. The star corner facets are at azimuth angles of 45, 135°, 225° and 315°. The crown upper angle facets (J) are preferably placed at angle of about 40° In case of cushion cut gemstones, upper corner facets (K) are placed preferably at an angle of 40°.
The pavilion is cut, chiselled and polished to have a plurality of pavilion facets, comprising of triangoid facets, chevron facets and pavilion main facets at heights, azimuth and facet angles in the manner known in the art, in the ratio of x: 4x:2x, where x is ≥4. The gemstone is cut and chiseled to form a plurality of triangoid facets (L), downwardly from the girdle, with triangle main angles (W) in the range of 55° to 65°. The chevron facets (M,N) comprising of pavilion lower half facets (M) and pavilion lower half corner facets (N), also are cut and polished, such that the chevron angles (X,X1) are in the range of 35° to 45°. The pavilion lower half corner facets (N) extend from the girdle to the culet. The pavilion lower half facets (M) extend downwardly from the triangoid facets to the culet. (D). To enable the invention, the chevron facets are cut and chiselled at heights, facet angles, and azimuth, such that 4 sided pavilion main facets (O) emerge upwardly from the culet. The pavilion main facets are preferably kite shaped having a common interphase with culet side ends of the chevron facets. The pavilion main facets are cut to have a pair of shortsides (P) and a pair of longsides (Q); The short sides (P) of the pavilion main facet are cut, chiselled and polished to converge at the culet and the long sides (Q) at 1st points (R) which are at a girdle depth in the range of 70 to 86%. Each of the pair of long side and short side are cut to converge at 2nd points (S) at a girdle depth varying from 88% to 96%. The facets are cut and polished in the aforesaid order, and arranged on either side of an axis line (C″) traversing the pavilion along a horizontal plane. Each pavilion facet is symmetrical with another across the axis line and all pavilion facets have one vertex pointing towards the culet. For the purpose of this embodiment, one pair of symmetrical pavilion main facets (O3,O6) which does not have any side along the axis plane, is cut to have a facet depth at the 1st point (R) to be less than the remainder 1st points by 0.5% to 10%, thus making this pair the longest pavilion main facet. The chevron facets (M.N) are cut and chiselled from the culet end side at the girdle depth of 70 to 86%, to form pairs of pavilion short half facets (T). A pair of adjacent symmetrical pavilion lower half facets having one common side along the axis is further cut, chiselled and polished at 1st pavilion angles at the girdle depth of the 1st point of pavilion main facets having the shortest girdle depth (O3, O6) with a variance of not more than 15%, from the point (V1) the axis line emerges on the pavilion surface to the 1st points of the pavilion main facets flanking such pavilion lower half facet. In a table view, the cable (RR) would appear to connect 1st points R3 and R4 at V1.
The adjacent pairs of short half facets have a 1st common interphase (P′), which is also the common interphase for the corresponding pair of pavilion lower half facets. The chevron facets are chiselled at 1st pavilion short half angles (Y) along a cable (RR) connecting the 1st points, to form the pavilion short half facets such that pairs of pavilion short half facets (T) alternate the long sides (Q) of the pavilion main facets (O). The pavilion short half facets are also symmetrical to the corresponding pavilion short half facet across the axis line. The 1st common interphase of the pavilion short half facets intersect the cable at (R′). The 1st pavilion short half angles are 15° to 30° less than the triangle main angle, and 2° to 9° less than the chevron angles (X,X−1).
In case of princess cut gemstones, as seen at
In case of cushion cut gemstones, as seen at
In both the princess cut and cushion cut gemstones, the angle along the 2nd common interphase of each facet of the pavilion mains (O) and the adjacent pavilion short half facets (T) are cut to vary in the range of 0.05° to 9°.
The pavilion main facets are further cut polished and chiselled at 2nd pavilion short lower half angles (Z) which are 0.25° to 8° less than 1st pavilion short half angles, at the girdle depth of the 2nd point (S). The angle so formed along the short side interphase (P) of adjacent pavilion main facets varies in the range of 0.05° to 9°.
In a commercial embodiment of the invention, the gemstone as described above is cut, chiselled and polished to have 8 pavilion main facets (O1 to O8) and 8 pavilion lower half facets (M1 to M8) and 8 pavilion lower half corner facets (N1 to N8)) and 16 pavilion short half facets (T1 to T16). The pair of pavilion main facets having the shortest girdle depth are identified as O3 and O6. The pairs of short half facets having a common side along the axis line are identified as T1,T16 and T8,T9. The small pavilion short half facets are identified as T8 and T9. The girdle depth of 1st pavilion short half angles (Y) range from 80-86%, and are ideally 2° to 6° less than the chevron angles (X,X−1). The gemstones are further cut and polished such that 1st pavilion short half angle of each pair of pavilion short half facets is at a variance of 0.20° to 2.0° with the 1st pavilion short half angle of the adjacent pair of pavilion short half facets. The pavilion main facet is also further cut and chiselled such that the 2nd pavilion short lower half angles (Z) at the 2nd point (S) is at a girdle depth ranging from 88.5 to 91%, and at least 0.4° to 2° less than the 1st pavilion short half angle. The pavilion mains (O) and the adjacent pavilion short half facets (T) are further cut, chiselled and polished such that the angle along the 2nd common interphase varies in the range of 0.20° to 6.0° and the angle along the 3rd common interphase varies in the range of 0.05° to 4.5°.
In another embodiment of this invention, 2nd pavilion short lower half angles are constant around the pavilion main facets (O).
In order to be able to get the perfect shape of the heart within the gemstone, with the indent the girdle depths of the 1st points have to be specific and the gemstone is cut and chiselled in specific relation to the girdle depth of the pavilion facet, having the shortest girdle depth. The suggested girdle depth of the 1st point of the pavilion main facet with the longest arms (O6) represented by R1 is 80% of the girdle depth and the subsequent 1st points of the pavilion main facets as represented by R2, R3, R4, R5, R6, R7, and R8 are at a depth of 1.05 R1, 1.04 R1, 1.04 R1, 1.05 R1, R1, 1.07 R1 and 1.07 R1. The girdle depth at which the common interphase between pairs of short half facets intersect the cable (RR) as represented by R′1, R′2, V1, R′4, R′5, R′6 and R′8 are at 1.03 R1, 1.05 R1, 1.03 R1, 1.04 R1, 1.03 R1, 1.01 and 1.01 R1. The girdle depth at which the common interphase between pairs of short half facets (T1, T16) emerges to the pavilion surface, from which point (V1) 1st pavilion angles are cut and chiselled along a cable to the 1st points of the nesting pavilion main facets (O1 and O8) is R1. In order to obtain a shape of the heart without the indent, the gemstone is cut and chiselled for the girdle depth of the 1st pavilion short half angle of the pavilion lower half facets with the 1st common interphase (P) on the axis line at’ R′7 to be about 1.07 R1.
These cuts are best viewed in gemstones having a minimum size of 10 cents. These facets can be hand cut and chiseled by a skilled workman in large size diamonds. In smaller size diamonds, the invention as disclosed are usually machine cut using computer algorithms based on the disclosed invention.
When viewed from the table facet the gemstone as described above, the cable joining the 1st points in the gemstone, form an outline of a heart shape (Z) along a horizontal plane. (
The above method is preferable applied to a gemstone like a diamond, which with its high refractive index, and the various intricate facet cuts as described above, could portray brilliance, even in ordinary light.
Number | Date | Country | Kind |
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201721006666 | Feb 2017 | IN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/IN2017/050445 | 10/4/2017 | WO | 00 |