Faceting Design Diagram: Reverse “P” – Tourmaline – Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


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

Reverse “P” (TLINE.JRG) 1.45 carat peach Tourmaline
By Jeff R. Graham
Copyright 1994
76.5% Light Return
Angles for R.I. = 1.62
43 facets + 6 facets on girdle = 49
6-fold, mirror-image symmetry
96 index
L/W = 1.155 T/W = 0.559 T/L = 0.485
P/W = 0.442 C/W = 0.213
H/W = (P+C)/W+0.02 = 0.675
P/H = 0.655 C/H = 0.315
Vol./W^3 = 0.263

Gram Book 1 – This design is unusual and not hard to cut. The P3 & P4 facets are a different size which gives the stone a very different flash. P4 facets cut very fast so watch out, 1/2-4cts any color med to light material. This design is surprisingly nice, give it a try… Cut in refractive index 1.62 to 1.93 (77.5%) 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.