Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)

Double Dart (TLINE64.JRG)
By Jeff R. Graham
Copyright 1998
88% Light Return
Angles for R.I. = 1.62
121 facets + 8 facets on girdle = 129
8-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.503 T/L = 0.503
P/W = 0.410 C/W = 0.202
H/W = (P+C)/W+0.02 = 0.632
P/H = 0.649 C/H = 0.319
Vol./W^3 = 0.207

Addition # 3 - This should be cut in a larger stone, the size of the P6,P7 are small and cut very fast. Some of these tiers have no meets, they have to be cut carefully. It can be hard to line up, medium material, 1-16cts. Cut in refractive indexes 1.62 to 1.93 (93%) with no changes.

 

 

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