Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)
Gambler (CHECK38.JRG)
By Jeff R. Graham
Copyright 2001
91.6% Light Return
Angles for R.I. = 1.62
65 facets + 16 facets on girdle = 81
4-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.298 T/L = 0.298
P/W = 0.405 C/W = 0.229
H/W = (P+C)/W+0.02 = 0.654
P/H = 0.619 C/H = 0.350
Vol./W^3 = 0.211
Addition # 6 – Cut this in any refractive index with no changes. This makes a nice round, especially in a large size so that the diamonds on the crown can be seen.
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.
