FIELD OF INVENTION: 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.

BACK GROUND :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 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.

US 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..

SUMMARY:

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 1 ^st 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 2 ^nd 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 1 ^st point, along a cable connecting the 1 ^st points, at 1 ^st 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. The2 ^nd 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 1 ^st 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 2 point and the angle so formed is 0.25° to 8° less than 1 ^st pavilion short half angles and referred to as 2 ^nd pavilion short lower half angles. Further the girdle depth of the 1 ^st point of one pair of symmetrical pavilion main facets is 0.5% to 10% less than the girdle depth of the 1 ^st 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 1 ^st 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 1 ^st pavilion short half angle of the adjacent pair of pavilion short half facets and the corresponding 2 ^nd pavilion short half angle may vary in the range of .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 1 ^st point ranges from 80-86%, and the girdle depth at the 2 ^nd 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 1 ^st pavilion short half angle of each of the pairs of pavilion short half facets is at a variance of .20 ° to 2.0 ° with the pavilion short half angle of the adjacent pair of pavilion short half facets and the 2 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 1 ^st point and the 2 ^nd 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 1 ^st 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. Drawings:

Fig 1 : The princess cut gemstone side view.

Fig 2 Table view of double crown princess cut gemstone

Fig 2 a: Crown top side angles of double crown princess cut gemstone.

Fig 3 : Pavilion view of princess cut gemstone

Fig 4: Exploded view of pavilion Main facets showing cable

Fig 4 (a) Exploded view of pavilion Main facets

Fig 4(b) Exploded view of pavilion main facets

Fig.5 :Pavilion angles in side view of a princess cut gemstone along pavilion lower half corner facet.

Fig. 5a :Pavilion angles in side view of a princess cut gemstone along pavilion lower half facet.

Fig 6: angles in pavilion view of a princess cut gemstone

Fig 6a: girdle depth of 1 st and 2nd Point on Pavilion of princess cut gemstone

Fig: 7 : table view of princesscut gemstone, showing heart shape in the centre.

Fig 8 : The cushion cut gemstone side view.

Fig 9: Table view of double crown cushion cut gemstone

Fig 9 (a) : Table side angle view of double crown cushion cut gemstone Fig 10 : Pavilion view of cushion cut gemstone

Fig: 1 1 : Pavilion angles in side view of a cushion cut gemstone along pavilion lower half facet

Fig 1 1 (a) Pavilion angles in side view of a cushion cut gemstone along pavilion lower half corner facet

Fig 12: angle variations of adjacent facets in cushion shaped diamond.

Fig 13 : girdle depth of 1 st and 2nd Point on Pavilion.

Fig: 14 : table view of cushion shaped gemstone, showing heart shape in the centre.

DESCRIPTION

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. ( Fig 7, 14) The gemstone of the present description , as commonly available in commerce, as seen in its side view ( Fig.1 , 8) is basically divided in to 3 regions: i. The upper face of the gemstone which is referred to as the upper crown table facet(A).ii.The region below the table facet is referred to as the girdle (B). iii. The lower part of the gemstone, i.e the region below the girdle is referred to as the pavilion(C ); The girdle separates and distinguishes the table facet from the pavilion .The lower most pointed tip of the pavilion is referred to as the culet (D) .

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 Figure 2, the table facet is comprised of a central table (Α'), 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 (.l)and crown upper angle facets( J) . In a preferred embodiment of the invention, as seen at Fig.2 in case of double crown princess cut gemstones, the table facet is comprised of a central table (Α') , surrounded by 4 crown-1 facets( Ei to E ₄ ) , 4 crown-2 facets (F to F ₄ ) _, 4 crown corner facets(Gi to G ₄ ), 4 star corner facets (H to H ₄ ), 8 star angle facets {\^ to l ₈ ) , and 8 upper angle facets(Ji to Js)

In case of a cushion cut gemstone , with a double crown, as seen in Fig 9, the table facet comprises of a central table (Α') , plurality of crown-1 facets(E), an equal number of crown-2 facets(F), half the number of crown corner facets (G) and star corner facets (H), and equal number of star angle facets (I) , crown upper angle facets( J) and upper corner facets (K);ln a preferred embodiment of the invention as seen at Fig.9 in case of double crown cushion cut gemstones, the table facet is comprised of a central table (Α') , 4 crown-1 facets( E-ito E ₄ ) , 4 crown-2 facets (Fi to F ₄ ) _, 4 crown corner facets(Gi to G ₄ ), 4 star corner facets (Hi to H ₄ ), 8 star angle facets ( to Is) , 8 upper angle facets(Ji to Js) and 8 upper angle corner facets ( K^o K ₈ ).

The crown angles on the Upper double crown table are at recommended angles as seen in Figure 2(a) and 9(a). The crown facet angles are usually in the range as seen in Table 1 below: TABLE 1

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 figure 3 and 10. the pavilion which has a plurality of pavilion facets on the pavilion surface, comprise of the following:( i)Triangoid facets (L) ,(ii). Chevron facets( M,N)comprising of equal number of pavilion lower half corner facets (N) and Substantially triangular pavilion lower half facets(M) ,(iii) pavilion Main facets (O ) and iv. Pairs of pavilion short half facets (T). All the facets have at least one vertice pointing towards the culet. (D) The pavilion facets are cut and chiselled to emerge upwardly from the culet(D) and are arranged on either side of an axis line (C-i) that traverses the pavilion along the horizontal plane. Each of the pavilion facets has a symmetrical pair across the axis line. 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 Fig.5. 5(a), 1 1 ,1 1 (a). The triangle main angle value and chevron angle value could vary over the above mentioned range, and the invention would not be affected.

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, (Fig 3) the triangoid facets(L) are substantially triangular and the chevron facets are comprised of equal number of pairs of substantially triangular and symmetrical, pavilion lower half facets(M) and pavilion lower half corner facets (N), with the chevron angles of pavilion lower half corner facets (X1 ) being 0.05° to 2.00° greater than the chevron angle of pavilion lower half facet (X) .

In a cushion cut gemstone, ( Fig 8, 10) the visually triangular triangoid facets are bounded on either sides of the vertex ( pointing to the culet) by two pairs of straight sides in an angular relation ranging from 175° to 1 79.95° , with an arcuate side facing that vertex.. The chevron facets are comprised of equal number of substantially triangular pavilion lower half facets(M) and polygoid pavilion lower half corner facets (N), having 3 straight sides and an arcuate side opposite to the vertex pointing towards the culet. The chevron angles (X1 ) of pavilion lower half corner facet is 0.05° to 2.00° greater than the chevron angle of pavilion lower half facet (X).

As seen in Fig 3 , 4, 4(a), 4(b) , and 10, the pavilion main facets (O) of a princess cut and cushion cut gemstone are similar in the number of pavilion lower half facets(M) and pavilion lower half corner facets(N). The pavilion main facet (O) are four sided and preferably kite shaped, emerging upwardly from the culet, with short sides(P) converging at the culet, long sides (Q) at 1 ^st points (R) at a girdle depth of 70 to 86 % and the long and short sides at 2 ^nd points(S) at a girdle depth of 88% to 95% . The girdle depth of the 1 ^st point of one pair of symmetrical pavilion main facets and is 0.5% to 10% less than the girdle depth of the 1 ^st point of the remainder pavilion main facets. (Fig 4, 6(a), 13.), thus making this pair the longest pavilion main facet. The girdle depth of the girdle is considered as 0% and that of the culet as 100%.

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 1 ^st pavilion angles around the depth of the 1 ^st point along a cable(RR) joining the 1 ^st points (R ). The angle formed by the pavilion short half facets and the remaining chevron facet is referred to as the 1 ^st pavilion short half angle. (Y). The 1 ^st pavilion angles are formed around the pavilion at a girdle depth of the 1 ^st point forming the cable (RR). The pairs of pavilion short half facets have a common side, referred to as the 1 ^st common interphase, which is continuous with the common side of the corresponding pairs of chevron facets. The 1 ^st 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 .( Fig 4, 4a,).

The 1 ^st 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 1 ^st pavilion short half angles(Y) corresponding to alternate pairs of chevron facets vary from 0.05° to 9° in the outer limit. ;(Fig .6, 12) . The pavilion main facets at the girdle depth of the 2 ^nd point are cut and chiselled at 2 ^nd pavilion short lower half angles(Z) which are 0.25° to 8° less than 1 ^st pavilion short half angles(Y). Thus the girdle depth of the final gemstone after chiselling the 2 ^nd pavilion short lower half angles, is less than the original gemstone The pavilion mains(O) facets and the adjacent pavilion short half facets(T) , along their common interphase ( referred to as the 2 ^nd common interphase) are at an angle which angle value varies amongst the 2 ^nd common interphases by 0.05° to 9°. The shortside interphase (Q) of adjacent pavilion main facets are also at an angle and the angle value varies in the range of 0.05°to 9°..

In a princess cut gemstone, the 1 ^st 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 1 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 1 ^st 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 1 ^st point ranges from 80-84.5%, and the facet depth at the 2 ^nd 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 1 ^st 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 1 ^st pavilion short half angle(T) of the adjacent pair of pavilion short half facets and the variation in the corresponding 2 ^nd pavilion short lower half angles (Z) is in the range of 0.05°to 4.0°. In another embodiment of this invention, the 2 ^nd 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( Oi to Os) and 8 pavilion lower half facets (Mi to M ₈ ) and 8 pavilion lower half corner facets(N to N ₈ ) ) and 16 pavilion short half facets( T to T ₆ ) . The pairs of pavilion short half facets with a common side along the axis line are T-i, Ti6, and T ₈ , T _g . The small pavilion short half facets are Ti, Ti ₆ ., and are nested between pavilion main facets O ₄ and O5. ( Fig 3, 4, 4a) The longest pavilion main facets are O ₃ and O _6, with 1 ^st points at about 81 % of the girdle depth. The girdle depth of the 1 ^st point (R) ranges from 80- 86%, and that of the 2 ^na point(S) ranges from 88.5 to 91 %.( Fig 6(a) ) Each facet of the pavilion mains(O) and the adjacent pavilion short half facets(T), along its common interphase are at an angular variance ranging from 0 .20° to 6.0° and the angular variance along the short side interphase of adjacent pavilion main facets(O) ranges from 0.05° to 4.5°. The 2 ^nd pavilion short lower half angle (Z) of the gemstone of this invention is at least 0.4° to 2° less than the corresponding 1 ^st pavilion short half angle(Y).( Fig 6)

In a precise embodiment of this invention as described above, the gemstone of cushion cut has 8 pavilion main facets( 01 to 08) 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( Ti to Ti ₆ ). The pairs of pavilion short half facets with a common side along the axis line are T-i, T ₆ , and T ₈ , T ₉ . The small pavilion short half facets are T-i, T ₆ ., and are nested between pavilion main facets O ₄ and O5. ( Fig 10, 4, 4a) The longest pavilion main facets are O3 and OQ, with 1 ^st points at about 81 % of the girdle depth. The pairs of pavilion short half facets with a common side along the axis line alone are symmetrical. The ideal girdle depth of 1 ^st point (R) ranges from 80-86%, and that of the 2 ^nd point(S) ranges from 88.5 to 91 %. Each facet of the pavilion mains(O) and the adjacent pavilion short half facets(T) along the common interphase are at an angular variance of 0 .20° to 6.0° in relation to each other and the angle of variance between culet side ends of adjacent pavilion main facets(O) along its common interphase ranges from .05° to 4.5°.. The 2 ^nd pavilion short lower half angle (Z) of the gemstone of this invention is at least 0.4° to 2° less than the corresponding 1 ^st pavilion short half angle(Y). 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 1 ^st point of the pavilion main facet with the longest arms represented by R-i , which is 80% of the girdle depth of the gemstone. The subsequent 1 ^st points of the pavilion main facets as represented by R ₂ , R3, R ₄ , R5, R6, R7, and R ₈ are at a depth of 1 .05Ri ,1 .04Ri, 1 .04Ri, 1 .05 Ri , Ri , 1 .07R ₁ and 1 .07 R ₁ The girdle depth at which the common interphase between pairs of short half facets intersect the cable (RR) as represented by R'-i, R' ₂ , V-i , R' ₄ , R' ₅ , R' ₆ , and R' ₈ are at 1 .03Ri , 1 .05Ri, 1 .03Ri , 1 .04R _{1 ;} 1 .03Ri, ,1 .01 Ri,1 .07Ri and 1 .01 Ri.

The sharpness of the shape of the heart within the gemstone is obtained by minimising the angular difference between the 1 ^st pavilion short half angles and the 2 ^nd pavilion short lower half angles.

In a commercially attractive embodiment of this invention in respect of princess cut and cushion cut gemstones, the 2 ^nd pair of pavilion short half facets having a common side along the axis line, at the azimuth angle of approximately160° 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 1 ^st point and 2 ^nd 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, (fig 7, 14)

The suggested girdle depths in order to create a heart shape design with an indent is in relation to the girdle depth of the 1 ^st point of the pavilion main facet with the longest arms represented by R-i , which is at 80% of the girdle depth and the subsequent 1 ^st points of the pavilion main facets as represented by R2, R3, R4, R5, R6, R7, and Rs are at a depth of 1.05Ri,1.04Ri, 1.04Ri, 1.05 Ri, Ri, 1.07R ₁ and 1.07 R ₁ . The the girdle depth at which the common interphase (Ρ') between pairs of short half facets intersect the cable (RR) as represented by R'i, R' ₂ , V-i, R' ₄ , R' ₅ , R'e, and R' ₈ are at 1.03Ri, 1.05Ri, Ri, 1.04Ri, 1.03Ri, ,1.01 Ri, and 1.01 Ri.

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 1 ^st pavilion short half angle and the 2 ^nd pavilion short lower half angle with reference to the girdle, where girdle is considered as 0 and culet as 100.

TABLE 2

At Fig. 6(a) , 13 is seen one such representation showing girdle depth at which desired results of a perfect heart shape is achieved.

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 1 pavilion short half angles and the 2 pavilion short lower half angles are around the gemstone.

TABLE 3

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. TABLE 4

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 (A-i), 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 (.l)and crown upper angle facets( J) . In a preferred embodiment of the invention, as seen at Fig.2 a double crown princess cut gemstones, the table facet is cut, chiseled and polished to comprised of a central table (Α') , surrounded by 4 crown-1 facets( E to E ₄ ) , 4 crown-2 facets (F to F ₄ ) _, 4 crown corner facets(Gi to G ₄ ), 4 star corner facets (Hi to H ₄ ), 8 star angle facets ( to Is) , and 8 upper angle facets(Ji to Js)

In case of a cushion cut gemstone , with a double crown, as seen in Fig 9, the upper crown table facet is cut , chiselled and polished to comprise of a central table (Α') , plurality of crown-1 facets(E), an equal number of crown-2 facets(F), half the number of crown corner facets (G) and star corner facets (H), and equal number of star angle facets (I) , crown upper angle facets( J) and upper corner facets (K); In a preferred embodiment of the invention as seen at Fig.9 in case of double crown cushion cut gemstones, the table facet is cut , chiselled and polished to comprise of a central table (Α') , 4 crown-1 facets( E-ito E ₄ ) , 4 crown-2 facets (Fi to F ₄ ) _, 4 crown corner facets(Gi to G ₄ ), 4 star corner facets (Hi to H ₄ ), 8 star angle facets ( to Is) , 8 upper angle facets(Ji to Js) and 8 upper angle corner facets ( K^o K ₈ ).

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 1 ^st 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 2 ^nd 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 (O) 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( O ₃ ,O ₆ ) which does not have any side along the axis plane , is cut to have a facet depth at the 1 ^st point( R) to be less than the remainder 1 ^st points by .5% to 1 0 %., 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 1 ^st pavilion angles at the girdle depth of the 1 ^st point of pavilion main facets having the shortest girdle depth (O3, Οβ) with a variance of not more than 1 5%, from the point (V-i) the axis line emerges on the pavilion surface to the 1 ^st points of the pavilion main facets flanking such pavilion lower half facet. In a table view, the cable (RR) would appear to connect 1 ^st points R3 and R ₄ at V-i . The adjacent pairs of short half facets have a 1 ^st common interphase(P'), which is also the common interphase for the corresponding pair of pavilion lower half facets. . The chevron facets are chiselled at 1 ^st pavilion short half angles(Y) along a cable(RR) connecting the 1 ^st 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 1 ^st common interphase of the pavilion short half facets intersect the cable at (R'). The 1 ^st pavilion short half angles are 1 5° 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 Fig 3, the chevron facets comprising of substantially triangular pavilion lower half facets(M) and pavilion lower half corner facets (N) are cut, chiselled and polished to have chevron angle(X)alongside the pavilion lower facet to be 0.05° to 2.00° less than the chevron angle (X-1 ) alongside the pavilion lower half corner facet. Further as seen at figure 6, the 1 ^st pavilion short half angles (Y) along the cable (R') of alternate adjacent pavilion short half facets from corresponding chevron facets are uniform , and having a variance of 0.05° to 8° with the adjacent pairs; In case of cushion cut gemstones, as seen at fig 10, the chevron facets are formed to comprise of substantially triangular pavilion lower half facets(M) and polygoid pavilion lower half corner facets (N) with an arcuate side opposite the vertex pointing to the culet. These facets are cut, chiselled and polished to have chevron angle(X)alongside the pavilion lower facet to be 0.05° to 2.00° less than the chevron angle (X-1 ) alongside the pavilion lower half corner facet. Further , as seen in Fig.12, the pairs of pavilion short half facets having a common side along the axis line are chiselled so that 1 ^st pavilion short half angles (Y) is the same as its adjacent pair. Further the 1 ^st pavilion short half angles (Y) of the remaining short half facets are cut, chiselled and polished to have a variance of 0.05° to 9° with its adjacent pair. The angle formed along the 2 ^nd common interphase (Q) of each facet of the pavilion main facet (O) and the adjacent pavilion short half facets(T) are further cut , chiselled and polished to have an angular variance in the range of 0.05° to 9° in its outer limit.,

In both the princess cut and cushion cut gemstones, the angle along the 2 ^nd 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 2 pavilion short lower half angles( Z) which are 0.25° to 8° less than 1 ^st pavilion short half angles, at the girdle depth of the 2 ^nd 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( Oi to 0s) and 8 pavilion lower half facets (M to M ₈ ) and 8 pavilion lower half corner facets(Ni to N ₈ ) ) and 16 pavilion short half facets( Ti to Ti ₆ ). The pair of pavilion main facets having the shortest girdle depth are identified as O ₃ and O ₆ . The pairs of short half facets having a common side along the axis line are identified as Τ _; Τ1 ₆ and T ₈ ,T ₉ . The small pavilion short half facets are identified as T ₈ and Tg. The girdle depth of 1 ^st 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 1 ^st pavilion short half angle of each pair of pavilion short half facets is at a variance of 0.20° to 2.0° with the 1 ^st 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 2 ^nd pavilion short lower half angles(Z) at the 2 ^nd point (S ) is at a girdle depth ranging from 88.5 to 91 %, and at least 0.4° to 2° less than the 1 ^st 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 2 ^nd common interphase varies in the range of 0.20° to 6.0° and the angle along the 3 ^rd common interphase varies in the range of 0.05° to 4.5°.

In another embodiment of this invention, 2 ^nd 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 1 ^st 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 1 ^st point of the pavilion main facet with the longest arms (O ₆ ) represented by R1 is 80% of the girdle depth and the subsequent 1 ^st points of the pavilion main facets as represented by R ₂ , R ₃ , R ₄ , R ₅ , Re, Rz, and R ₈ are at a depth of 1 .05R1 ,1 .04R1 , 1 .04R1 , 1 .05 R1 , R1 , 1 .07R1 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'i, R' ₂ , Vi, R' ₄ , R' ₅ , R'e and R' ₈ are at 1 .03R1 , 1 .05R1 , 1 .03R1 , 1 .04R1 , 1 .03R1 , ,1 .01 R1 and 1 .01 R1 . The girdle depth at which the common interphase between pairs of short half facets( T-i , T ₆ ) emerges to the pavilion surface, from which point (V-i) 1 ^st pavilion angles are cut and chiselled along a cable to the 1 ^st points of the nesting pavilion main facets( O ₁ and Os) is R-i. In order to obtain a shape of the heart without the indent, the gemstone is cut and chiselled for the girdle depth of the 1 ^st pavilion short half angle of the pavilion lower half facets with the 1 ^st common interphase( P) on the axis line at ' R' ₇ to be about 1 .07R1 . 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 1 ^st points in the gemstone, form an outline of a heart shape (Z) along a horizontal plane. ( Fig 7, fig 14) 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.