Faceting Design Diagram: Tabish – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite

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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

Gram Faceting Archive of Information
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.