Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)
Vampire (CHECK40.JRG)
By Jeff R. Graham
Copyright 2001
88.6% Light Return
Angles for R.I. = 1.62
45 facets + 16 facets on girdle = 61
2-fold, mirror-image symmetry
96 index
L/W = 1.247 T/W = 0.248 T/L = 0.199
P/W = 0.447 C/W = 0.178
H/W = (P+C)/W+0.02 = 0.645
P/H = 0.693 C/H = 0.276
Vol./W^3 = 0.317
Addition # 6 – This works in refractive indexes 1.62 to 1.93 with no changes. It is especially good in Garnet (89.6%), and is good for saturated materials.
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.
