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


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

Roval Brilliant (MC39.JRG)
By Jeff R. Graham
Copyright 1999
89.9% Light Return
Angles for R.I. = 1.62
49 facets + 10 facets on girdle = 59
2-fold, mirror-image symmetry
96 index
L/W = 1.414 T/W = 0.749 T/L = 0.530
P/W = 0.615 C/W = 0.210
H/W = (P+C)/W+0.02 = 0.844
P/H = 0.728 C/H = 0.248
Vol./W^3 = 0.516

Addition # 4 – This is more of a brilliant top design, it works well with about any material. The yield is very high and it cuts easily. It works well with a trillion on either side, 1cts+. Cut this in R.I. 1.62 to 1.93 (90.5%) without 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.