Faceting Design Diagram: 4X Square – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

4X Square (TLINE12.JRG)
By Jeff R. Graham
Copyright 1994
81.6% Light Return
Angles for R.I. = 1.62
53 facets + 12 facets on girdle = 65
4-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.479 T/L = 0.479
P/W = 0.450 C/W = 0.198
H/W = (P+C)/W+0.02 = 0.669
P/H = 0.673 C/H = 0.297
Vol./W^3 = 0.267

Gram Book 1 – Here is a nice modified square that cuts fast and has a very nice flash. It can be cut in about any size or material, 1/2-6cts. Cut in refractive index 1.62 to 2.14 (83.8%) with no 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.