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

“Streeeech” (TLINE62.JRG)
By Jeff R. Graham
Copyright 1998
72% Light Return
Angles for R.I. = 1.62
31 facets + 4 facets on girdle = 35
2-fold, mirror-image symmetry
96 index
L/W = 4.000 T/W = 3.491 T/L = 0.873
P/W = 0.602 C/W = 0.229
H/W = (P+C)/W+0.02 = 0.851
P/H = 0.707 C/H = 0.269
Vol./W^3 = 1.972

Addition # 2 - This works best on open "c" axis Tourmaline. A preform is needed 4.0 L/W. The crown can be cut as low as 32 degrees (10 degrees off of all the crown tiers), 2-18cts.

 

 

 

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