Facet patterns and arrangements for gemstones

Abstract

The present invention relates to the cut of a gemstone, and particularly to facet patterns and arrangements for modified round brilliant cut gemstones having fifty-eight facets. In one embodiment, a facet pattern for the crown of a gemstone includes an octagonal facet; a plurality of triangular star facets; a plurality of triangular upper main facets; a plurality of upper girdle facets; a plurality of quadrilaterals lower main facets, a plurality of triangular lower main facets, and a plurality of lower girdle facets. Both the lower and upper girdle facets have at least one scalloped edge.

1 . A facet pattern and arrangement for a crown of a gemstone comprising:
 an octagonal facet;   a first plurality of triangular facets;   a second plurality of triangular facets; and   a plurality of upper girdle facets having four upper girdle facet edges.   
     
     
         2 . The facet pattern and arrangement of  claim 1 , wherein the octagonal facet is a table facet. 
     
     
         3 . The facet pattern and arrangement of  claim 1 , wherein the first plurality of triangular facets is star facets. 
     
     
         4 . The facet pattern and arrangement of  claim 1 , wherein the second plurality of triangular facets is upper main facets. 
     
     
         5 . The facet pattern and arrangement of  claim 1 , wherein at least one upper girdle facet edge is scalloped. 
     
     
         6 . The facet pattern and arrangement of  claim 1 , wherein the facet pattern and arrangement has twenty-five facets. 
     
     
         7 . The facet pattern and arrangement of  claim 1 , wherein the second plurality of triangular facets has eight facets. 
     
     
         8 . The facet pattern and arrangement of  claim 1 , wherein the plurality of upper girdle facets has eight facets. 
     
     
         9 . The facet pattern and arrangement of  claim 1 , wherein the upper girdle facet edges form a trapezoid. 
     
     
         10 . A facet pattern and arrangement for a pavilion of a gemstone comprising:
 a plurality of quadrilaterals facets,   a first plurality of triangular facets,   a second plurality of triangular facets, and   a plurality of lower girdle facets having three lower girdle facet edges.   
     
     
         11 . The facet pattern and arrangement of  claim 10 , wherein at least one of the lower girdle facet edges is scalloped. 
     
     
         12 . The facet pattern and arrangement of  claim 10 , wherein two lower girdle facet edges have substantially equal length. 
     
     
         13 . The facet pattern and arrangement of  claim 10 , wherein the plurality of quadrilaterals facets has eight facets. 
     
     
         14 . The facet pattern and arrangement of  claim 10 , wherein the first plurality of triangular facets has eight facets. 
     
     
         15 . The facet pattern and arrangement of  claim 10 , wherein the second plurality of triangular facets has eight facets. 
     
     
         16 . The facet pattern and arrangement of  claim 10 , wherein the plurality of lower girdle facets has eight facets. 
     
     
         17 . The facet pattern and arrangement of  claim 10 , further comprising a culet facet. 
     
     
         18 . The facet pattern and arrangement of  claim 17 , wherein the facet pattern and arrangement has thirty-three facets. 
     
     
         19 . A facet pattern and arrangement for a gemstone comprising:
 an octagonal table facet;   a plurality of triangular star facets;   a plurality of upper main facets;   a plurality of upper girdle facets having four upper girdle facet edges;   a plurality of quadrilateral lower main facets;   a plurality of left-sided lower main facets;   a plurality of right-sided lower main facets;   a plurality of lower girdle facets; and   a culet facet.   
     
     
         20 . The facet pattern and arrangement of  claim 19 , wherein each upper main facet has three upper main facet edges. 
     
     
         21 . The facet pattern and arrangement of  claim 20 , wherein at least one upper girdle facet edge is scalloped. 
     
     
         22 . The facet pattern and arrangement of  claim 19 , wherein each lower girdle facet has at least three edges. 
     
     
         23 . The facet pattern and arrangement of  claim 22 , wherein at least one lower girdle facet edge is scalloped. 
     
     
         24 . The facet pattern and arrangement of  claim 19 , wherein the facet pattern and arrangement has fifty-eight facets. 
     
     
         25 . A gemstone comprising:
 a crown having a plurality of upper girdle facets with four upper girdle facet edges, wherein at least one upper girdle facet edge is scalloped;   a pavilion; and   a girdle.   
     
     
         26 . The gemstone of  claim 25 , wherein the gemstone has a plurality of lower girdle facets with three lower girdle facet edges. 
     
     
         27 . The gemstone of  claim 26 , wherein at least one lower girdle facet edge is scalloped. 
     
     
         28 . The gemstone of  claim 26 , wherein two lower girdle facets have substantially equal length. 
     
     
         29 . The gemstone of  claim 25 , further comprising a culet. 
     
     
         30 . The gemstone of  claim 29 , wherein the gemstone has fifty-eight facets.