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

T-Tipped Tri (TLINE38.JRG)
By Jeff R. Graham
Copyright 1997
78.4% Light Return
Angles for R.I. = 1.62
58 facets + 6 facets on girdle = 64
3-fold, mirror-image symmetry
96 index
L/W = 1.155 T/W = 0.556 T/L = 0.481
P/W = 0.486 C/W = 0.209
H/W = (P+C)/W+0.02 = 0.715
P/H = 0.679 C/H = 0.293
Vol./W^3 = 0.260

Addition # 2 - This is hard to cut because of the small crown facets. It should be cut in a larger size and lighter material. The C4,C5 facets are not cut to center point, and on a smaller stone might have to be hand-lapped, 3- 16cts. Cut in refractive indexes 1.62 to 1.93 with no changes.

 

 

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