Faceting Design Diagram: Bag of Diamonds – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

Bag of Diamonds (CHECK55.JRG)
By Jeff R. Graham
Copyright 2003
86.4% Light Return
Angles for R.I. = 1.62
27 facets + 8 facets on girdle = 35
2-fold, mirror-image symmetry
96 index
L/W = 2.000 T/W = 0.961 T/L = 0.480
P/W = 0.418 C/W = 0.204
H/W = (P+C)/W+0.02 = 0.642
P/H = 0.651 C/H = 0.318
Vol./W^3 = 0.640

Addition # 8 – The diamonds will vary a bit depending on the C1,C4 tiers. Cut the table in and then the C6 to meet makes it easier. This is designed for Tourmaline, but will work well in refractive indexes 1.62 to 1.93 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.