Delta: Faceting Design Diagram

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

Delta (CHECK56.JRG)
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