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


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

Delta (CHECK56.JRG)Delta cut by Tony Carsone in Tourmaline
By Jeff R. Graham
Copyright 2002
86.8% Light Return
Angles for R.I. = 1.62
46 facets + 9 facets on girdle = 55
3-fold, mirror-image symmetry
96 index
L/W = 1.021 T/W = 0.290
|T/L = 0.284 P/W = 0.417 C/W = 0.221
H/W = (P+C)/W+0.02 = 0.657
P/H = 0.634 C/H = 0.336
Vol./W^3 = 0.226

Addition # 8 – The crown is deep and I generally cut this in light colors, although it will work well in medium colored material too. This is nice in Zambian Tourmaline nodules.


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.