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

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

Tack – Reflector (CHECK3.JRG)3.08 carat Tourmaline
By Jeff R. Graham
Copyright 2000
88.9% Light Return
Angles for R.I. = 1.62
37 facets + 8 facets on girdle = 45
4-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.235 T/L = 0.235
P/W = 0.478 C/W = 0.206
H/W = (P+C)/W+0.02 = 0.704
P/H = 0.679 C/H = 0.293
Vol./W^3 = 0.300

Addition # 6 – This is a neat one, the flashes are a true check. Notice that the corners float, this is to help get yield if your rough is not just right. Cut the corners in as close as you can to the diagram. If you are a bit off it will not really change much. I designed this for a piece of light multi-colored Tourmaline.

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.