Faceting Design Diagram: Star “M” – Sapphire / Corundum – Ruby, Ceylon, Padparadschah, Pink, Yellow, Green


Sapphire / Corundum (Ruby, Ceylon, Padparadschah, Pink, Yellow, Green)

Star “M” (SAP12.JRG)
By Jeff R. Graham
Copyright 1995
82.2% Light Return
Angles for R.I. = 1.76
65 facets + 8 facets on girdle = 73
8-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.544 T/L = 0.544
P/W = 0.442 C/W = 0.218
H/W = (P+C)/W+0.02 = 0.680
P/H = 0.650 C/H = 0.320
Vol./W^3 = 0.261

Gram Book 1 – This design cuts simple and it gives a nice flash in about any color of material. It is nice to use for Montana rough that seems to come in rounded shapes, but not always chunky, 1/2-2cts+. Cut in refractive index 1.78 to 2.14 (83.6%) 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.