Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)
Tabish (CHECK26.JRG)
By Jeff R. Graham
Copyright 2001
93% Light Return
Angles for R.I. = 1.62
39 facets + 12 facets on girdle = 51
2-fold, mirror-image symmetry
96 index
L/W = 1.163 T/W = 0.211 T/L = 0.182
P/W = 0.450 C/W = 0.230
H/W = (P+C)/W+0.02 = 0.700
P/H = 0.643 C/H = 0.328
Vol./W^3 = 0.306
Addition # 6 – Notice that the ends float, P6 does not cut to center point. Make the girdle facets as equal as you can, but the stone can be varied L/W without causing much problem. This can be cut in refractive indexes 1.62 to 1.93 with no changes. This design makes a very bright stone and works well in darker 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.
