Faceting Design Diagram: Little Block – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

Little Block (TLINE35.JRG)
By Jeff R. Graham
Copyright 1996
84.4% Light Return
Angles for R.I. = 1.62
45 facets + 8 facets on girdle = 53
4-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.356 T/L = 0.356
P/W = 0.423 C/W = 0.297
H/W = (P+C)/W+0.02 = 0.740
P/H = 0.572 C/H = 0.401
Vol./W^3 = 0.301

Addition # 1 – This design is for those chunky pieces of rough that are really too square to cut a round out of. I designed it for that light pastel Afghan Tourmaline that is available once and a while (it will help darken color). It cuts easy and the crown facets can be brought down a few degrees, if needed, 1/2-8cts (finished). Cut in refractive indexes 1.62 to 1.76 with no changes. This works best in light colored material.

 


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.