Gem having a stellar appearance

Abstract

Disclosed is a gem ( 1 ) that has a stellar appearance. Said gem ( 1 ) comprises a crown ( 2 ) having a plurality of crown facets, including a first group ( 6 ) of crown facets that taper in the direction of a girdle ( 4 ) and extend at an angle (a) of 22.5°±3°, preferably 22.5°+2° from the girdle plane (E), and a second group ( 7 ) of crown facets that adjoin the girdle ( 4 ) by their large side and extend at an angle ( 13 ) of 34°±3°, preferably 34°±2° from the girdle plane (E). Also disclosed is an arrangement comprising a gem.

1 . A gem having a stellar appearance, wherein the gem has a crown having a plurality of crown facets, and a first group of crown facets tapering towards a girdle has an angle a of 22.5°±3°, preferably 22.5°+2° relative to the girdle plane, and a second group of crown facets which with their wide side adjoin the girdle has an angle β of 34°±3°, preferably 34°+2° relative to the girdle plane. 
     
     
         2 . A gem as set forth in  claim 1  wherein the gem has a pavilion having a plurality of pavilion facets, wherein a first group of pavilion facets tapering towards the girdle has an angle γ of 43.5°+3°, preferably 43.5°+2° relative to the girdle plane and a second group of pavilion facets which with a wide side adjoin the girdle has an angle δ of 50°+3°, preferably 50°+2° relative to the girdle plane. 
     
     
         3 . A gem as set forth in  claim 1 , wherein in plan view the gem has a pentagonal contour. 
     
     
         4 . A gem as set forth in  claim 1 , wherein the gem consists of a material transparent for the visible spectrum of light and has a refractive index of between 2.0 and 2.4. 
     
     
         5 . A gem as set forth in  claim 1 , wherein the gem consists of cubic zirconia. 
     
     
         6 . A gem as set forth in  claim 1 , wherein the contrast of the light return between the first group of facets tapering towards the girdle and the second group of facets tapering towards the middle, determined in each case at a position measured radially outwardly from the longitudinal axis of the gem, of two thirds of the radius of a peripheral circumcircle extending around the contour of the gem in the respective angle bisector of the respective facet, is at least 50%, preferably at least 70% , particularly preferably at least 80%. 
     
     
         7 . An arrangement comprising:
 a gem, in particular as set forth in  claim 1 ,   a setting, wherein claws of the setting engage over the edge of the gem,   wherein the claws are so shaped and preferably arranged in the region of the second group of crown facets that the visible surface of the gem is delimited by an alternately convex and concave edge line.   
     
     
         8 . An arrangement as set forth in  claim 7 , wherein the visible surface of the gem forms the surface of a five-ray star. 
     
     
         9 . A gem as set forth in  claim 2 , wherein in plan view the gem has a pentagonal contour. 
     
     
         10 . A gem as set forth in  claim 2 , wherein the gem consists of a material transparent for the visible spectrum of light and has a refractive index of between 2.0 and 2.4. 
     
     
         11 . A gem as set forth in  claim 3 , wherein the gem consists of a material transparent for the visible spectrum of light and has a refractive index of between 2.0 and 2.4. 
     
     
         12 . A gem as set forth in  claim 9 , wherein the gem consists of a material transparent for the visible spectrum of light and has a refractive index of between 2.0 and 2.4. 
     
     
         13 . A gem as set forth in  claim 2 , wherein the gem consists of cubic zirconia. 
     
     
         14 . A gem as set forth in  claim 3 , wherein the gem consists of cubic zirconia. 
     
     
         15 . A gem as set forth in  claim 4 , wherein the gem consists of cubic zirconia. 
     
     
         16 . A gem as set forth in  claim 9 , wherein the gem consists of cubic zirconia. 
     
     
         17 . A gem as set forth in  claim 10 , wherein the gem consists of cubic zirconia. 
     
     
         18 . A gem as set forth in  claim 11 , wherein the gem consists of cubic zirconia. 
     
     
         19 . A gem as set forth in  claim 12 , wherein the gem consists of cubic zirconia. 
     
     
         20 . A gem as set forth in  claim 2 , wherein the contrast of the light return between the first group of facets tapering towards the girdle and the second group of facets tapering towards the middle, determined in each case at a position measured radially outwardly from the longitudinal axis of the gem, of two thirds of the radius of a peripheral circumcircle extending around the contour of the gem in the respective angle bisector of the respective facet, is at least 50%, preferably at least 70% , particularly preferably at least 80%.