a diamond is a crystal which functions as a prism for dispersing light by means of reflection and refraction . a traditional cut triangular diamond is shown in fig1 a - 1c and possesses three main crown facets and three main pavilion facets with the facets positioned in line with the shape of the diamond . in sharp contrast , the triangular shaped diamond of the present invention 10 is cut , as is shown in fig2 - 10 and more specifically as shown in fig2 , to form six main crown facets identified by the letters : a , b , c , d , e and f with each of the six main crown facets having a substantially equal and oppositely positioned facet and with at least one edge in each main crown facet having a corresponding edge in parallel alignment in the oppositely positioned main crown facet . for example , facet a lies opposite facet d with each of the facets a and d having parallel edges 12 and 13 . the six main crown facets a through f surround a table facet t . the triangular shaped diamond 10 should include three main girdle facets gfa , gfb and gfc and six subsidiary girdle facets sa 1 , sa 2 , sb 1 , sb 2 , sc 1 , sc 2 respectively . fig5 is a top view of the triangular shaped diamond 10 showing the arrangement between the three main girdle facets gfa , gfb and gfc and the six subsidiary girdle facets sa 1 , sa 2 , sb 1 , sb 2 , sc 1 , sc 2 . the six main crown facets a - f are preferably polished on the diamond 10 after the table area is polished into a smooth table facet t and in parallel alignment to the six subsidiary girdle facets sa 1 , sa 2 , sb 1 , sb 2 , sc 1 , sc 2 . however , the subsidiary girdle facets sa 1 , sa 2 , sb 1 , sb 2 , sc 1 , sc 2 are not in alignment with the main girdle facets gfa , gfb and gfc . this permits the six main crown facets a - f to be polished with each main crown facet having a substantially identical and parallel opposite main crown facet . moreover , the six main crown facets a - f should be polished within an angle degree range of 33 . 8 °- 35 . 2 °. the subsidiary girdle facets sa 1 and sa 2 should preferably be polished at 30 ° from the main girdle facet gfa with the subsidiary girdle facets sb 1 and sb 2 polished at 30 ° from the main girdle facet gfb and the subsidiary girdle facets sc 1 and sc 2 polished at 30 ° from the main girdle facet gfc . the triangular shaped diamond 10 should include six main pavilion facets pea , pfb , pfc , pfd , pfe and pff in an arrangement with three subsidiary pavilion facets i , ii and iii as shown in fig3 or without any subsidiary pavilion facets as shown in fig4 . the three subsidiary pavilion facets are optional and should preferably be included when the diamond to be cut is a thick diamond as opposed to a relatively thin diamond . each of the six main pavilion facets pfa - pff are polished at 60 ° from each adjacent main pavilion facet and should each be aligned with the six main crown facets a - f and the six subsidiary girdle facets sa 1 , sa 2 , sb 1 , sb 2 , sc 1 , sc 2 respectively . accordingly , the main pavilion facet pfa should be polished at 60 ° from facet pfb and facet pfb should be polished at 60 ° from facet pfc etc . when the three subsidiary pavilion facets are included in the triangular shaped diamond 10 they should be aligned parallel to the three main girdle facets within an angle degree range of 65 °- 72 °. the triangular shaped diamond 10 should include twelve pavilion half facets identified by the letters : a , b , c , d , e , f , g , h , i , j , k and l respectively . each pavilion half facet should preferably be polished within an angle degree range of 41 . 9 °- 42 . 9 °. the twelve pavilion half facets ( a - l ) are shown in an arrangement with the six main pavilion facets ( pfa - pff ) and with the three subsidiary pavilion facets ( i , ii , iii ) in fig6 and without any subsidiary pavilion facets in fig7 . all of the twelve pavilion half facets a - l should preferably be polished to an identical angle and should preferably meet adjacent pavilion half facets at a point . in addition , the six pavilion half facets a , b , e , f , i and j should each preferably be polished to within a depth range of 42 . 4 °- 49 . 2 ° depending upon the stone &# 39 ; s total depth whereas the other six pavilion half facets c , d , g , h , k and l should each preferably be polished within the depth range of 40 . 8 °- 42 . 8 °. however , when the triangular shaped diamond 10 includes the three subsidiary pavilion facets ( i , ii , iii ) the pavilion half facets c - l have a lower depth range because of the presence of the three subsidiary pavilion facets ( i , ii , iii ) as shown in fig6 than in the counterpart arrangement without any subsidiary pavilion facets as shown in fig7 . the triangular shaped diamond 10 should also include three crown star facets sf 1 , sf 11 and sf 111 respectively within an angle degree range of 18 . 6 °- 24 . 2 ° and twelve crown half facets cfa , cfb , cfc , cfd , cfe , cff , cfg , cfh , cfi , cfj , cfk and cfl respectively . it should be noted that it is unusual to have an unequal number of crown star facets relative to the number of main crown facets . however , it was discovered that having star facets on the main girdle sides distorts light refraction . it should also be noted that it is preferable for each of the six crown half facets cfa , cfb , cfe , cff , cfi and cfj to be polished within an angle degree range of 37 . 0 °- 40 . 4 ° while each of the other six crown half facets cfc , cfd , cfg , cfh , cfk and cfl are polished at an angle degree range of 48 . 0 °- 50 . 8 °. the triangular shaped diamond of the present invention will yield a hearts and arrows pattern substantially equivalent to the hearts and arrows pattern of the round cut when cut to satisfy the optimum parameters set forth below in table i : the diamond should be measured repeatedly as to insure the cut parameters are obtained . the angles and dept size should be verified for accuracy using conventional analyzers .
a triangular shaped diamond adapted to display a hearts and arrows pattern when exposed to light comparable to the hearts and arrows pattern in a round diamond , comprising : six main crown facets , twelve crown half facets , a table facet , six main pavilion facets and a plurality of girdle facets separating the crown facets from the pavilion facets with each main crown facet having a symmetrically positioned opposite crown facet of substantially equal size surrounding the table facet and having at least one edge in parallel alignment with a corresponding edge in the main crown facet opposite thereto .