Faceting Design Diagram: “88” Around – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

“88” Around (MC17.JRG)
By Jeff R. Graham
Copyright 1999
83% Light Return
Angles for R.I. = 1.62
61 facets + 8 facets on girdle = 69
4-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.531 T/L = 0.531
P/W = 0.445 C/W = 0.182
H/W = (P+C)/W+0.02 = 0.648
P/H = 0.688 C/H = 0.281
Vol./W^3 = 0.228

Addition # 4 – This one is a nice change from a regular “RB”. I use it in light to medium material, it is great in pink Tourmaline from Nigeria. It is pretty easy, 2cts+. Works in Topaz and Peridot also… Cut this in R.I. 1.62 to 2.14 (92.1%) 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.