Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)
Flutter (CHECK79.JRG)
By Jeff R. Graham
Copyright 2003
81.5% Light Return
Angles for R.I. = 1.62
35 facets + 12 facets on girdle = 47
2-fold, mirror-image symmetry
96 index
L/W = 1.200 T/W = 0.349 T/L = 0.291
P/W = 0.436 C/W = 0.230
H/W = (P+C)/W+0.02 = 0.686
P/H = 0.636 C/H = 0.335
Vol./W^3 = 0.234
Addition # 8 – Cut in refractive indexes 1.62 to 2.14 (86.4%) with no changes. This cuts easily with no real surprises.
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.
