Faceting Design Diagram: H & H Crown Rectangle – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

H&H Crown Rectangle (TLINE5.JRG)
By Jeff R. Graham
Copyright 1993
70.5% Light Return
Angles for R.I. = 1.62
43 facets + 12 facets on girdle = 55
2-fold, mirror-image symmetry
96 index
L/W = 1.450 T/W = 0.712 T/L = 0.491
P/W = 0.440 C/W = 0.212
H/W = (P+C)/W+0.02 = 0.673
P/H = 0.655 C/H = 0.315
Vol./W^3 = 0.373

Gram Book 1 – This design is good for rectangular material and gives a much better light return than the 70.5% that ray traced. It can be cut in another order. It’s not hard to cut and works well in light to med material, this works well in Topaz.

 

 


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.