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

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Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)

Asterism Jeff Graham Facet Design

Asterism Jeff Graham Facet Design

Asterism (MC108.JRG)
By Jeff R. Graham
Copyright 2006
78.6% Light Return Angles for
R.I. = 1.62
145 facets + 16 facets on girdle = 161
8-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.350 T/L = 0.350 P/W = 0.431
C/W = 0.206 H/W = (P+C)/W+0.02 = 0.657 P/H = 0.656 C/H = 0.314 Vol./W^3 = 0.211

Addition # 12 – Cut this in refractive indexes 1.62 to 2.14 with no changes. This works well in light to medium saturated materials and it should be cut at least 10mm or larger. This is easy to cut and very bright.

Asterism Jeff Graham Facet Design

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.