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

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

Long Diamond (CHECK67.JRG) Afgan Bi-Color Tourmaline
By Jeff R. Graham
Copyright 2003
84.5% Light Return
Angles for R.I. = 1.62
27 facets + 4 facets on girdle = 31
2-fold, mirror-image symmetry
96 index
L/W = 2.001 T/W = 0.967 T/L = 0.483
P/W = 0.420 C/W = 0.300
H/W = (P+C)/W+0.02 = 0.740
P/H = 0.567 C/H = 0.405
Vol./W^3 = 0.896

Addition # 8 – This is a good design for about any Tourmaline, it’s a nice change from a regular rectangle. This works best in 1.62 but can be cut in refractive index up to 2.14 with no changes.


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.