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


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

Primal Construct (MIR30.JRG)
By Jeff R. Graham
Copyright 2004
88.2% Light Return
Angles for R.I. = 1.62
45 facets + 8 facets on girdle = 53
4-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.368 T/L = 0.368
P/W = 0.435 C/W = 0.229
H/W = (P+C)/W+0.02 = 0.684
P/H = 0.635 C/H = 0.335
Vol./W^3 = 0.259

Addition # 9 – This cuts a very bright stone and works well in medium saturated materials and, in particular, Garnets. This cuts fast and I prefer it in a large size stone. It makes excellent earrings, cut in refractive indexes 1.62 to 1.76 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.