Cut gem and article comprising such a gem

Abstract

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

1 . A cut gem comprising:
 a girdle having four girdle sides and four girdle vertices,   a table formed by a flat facet,   a crown which extends between the table and the girdle, in a first direction,   and a pavilion extending in a second direction, opposite to said first direction, between said girdle and a pavilion tip,   wherein the crown has twenty-four facets, the pavilion has thirty-two facets, and the four girdle sides are identical in the form of an arc of a circle, of which the concavity is oriented towards the outside of the gem.   
     
     
         2 . The cut gem according to  claim 1 , wherein said crown comprises:
 four table corner facets positioned at the four corners of the table,   four sides, each of the four sides of the crown comprising:   at least one break facet,   a first crown star facet positioned between the break facet and a first table corner facet, and   a second crown star facet positioned between the break facet and a second table corner facet.   
     
     
         3 . The cut gem according to  claim 2 , wherein the twenty-four facets of the crown comprise four lateral faces, four bezel facets, four break facets, eight star facets, and four table corner facets. 
     
     
         4 . The cut gem according to  claim 3 , wherein:
 the table lies in a table plane,   each bezel facet lies in a bezel plane,   and wherein a bezel plane is inclined relative to the table plane at an angle substantially between 35 and 39°.   
     
     
         5 . The gem according to  claim 1 , wherein said pavilion comprises:
 four pavilion break facets,   a pavilion star having four pavilion star facets connecting the pavilion tip and the girdle vertices, and   at least three lower pavilion facets positioned on each side of each pavilion star facet, between a pavilion star facet and a pavilion break facet among said four break facets.   
     
     
         6 . The cut gem according to  claim 5 , wherein the thirty-two facets of the pavilion comprise four pavilion break facets, four pavilion star facets, and twenty-four lower pavilion facets. 
     
     
         7 . The cut gem according to  claim 5 , wherein:
 the table lies in a table plane,   each pavilion break facet lies in a pavilion break plane   and wherein each pavilion break plane is inclined relative to the table plane at an angle substantially between 58 and 62°.   
     
     
         8 . The cut gem according to  claim 5 , wherein:
 each girdle side has a girdle side length (L) which is the shortest distance between two adjacent girdle vertices,   said pavilion star has a base of square cross-section near the pavilion tip,   and wherein the base of square cross-section has a diagonal whose length is substantially between 5 and 11% of the girdle side length.   
     
     
         9 . The cut gem according to  claim 1 , wherein:
 each girdle side has a girdle side length which is the shortest distance between two adjacent girdle vertices,   each girdle side has a maximum depth perpendicular to a line connecting the two adjacent girdle vertices,   and wherein said maximum depth substantially corresponds to between 5.5 and 9.5% of said girdle side length.   
     
     
         10 . The cut gem according to  claim 1 , wherein:
 each girdle side has a girdle side length which is the shortest distance between two adjacent girdle vertices,   the table has eight table vertices, of which four table vertices are also table corners and the four other vertices, alternating with the table corners, are also break facet vertices,   and wherein the distance between a break facet vertex and the line connecting the two adjacent girdle vertices, perpendicular to said line, is substantially between 18 and 22% of said girdle side length.   
     
     
         11 . The ccut gem according to  claim 1 , wherein the gem is a diamond. 
     
     
         12 . The article of jewelry comprising at least one gem according to  claim 1 .