Faceting Design Diagram: 8-12 Star – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite

by

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

8-12 Star (TLINE21.JRG)
By Jeff R. Graham
Copyright 1995
70.3% Light Return
Angles for R.I. = 1.62
77 facets + 8 facets on girdle = 85
4-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.454 T/L = 0.454
P/W = 0.493 C/W = 0.224
H/W = (P+C)/W+0.02 = 0.737
P/H = 0.669 C/H = 0.304
Vol./W^3 = 0.276

Addition # 1 – The P1,P2(G),P3 facets can be cut in another order if you want. It could be cut P2(G),P3,P1, use whatever works for you, light to medium material 1-12cts. Cut in refractive indexes 1.62 to 1.93 (89.1%) with no changes. Notice that this is a deep design and it will work well in light colored materials.

 


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.