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.
Random – Cosine – ISO
Detailed faceting instructions by Jeff Graham available at The Rock Peddler
This edited version of an article by the late Jeff Graham is part of a special archived informational series from Gram Faceting. Used with permission.
