Faceting Design Diagram: Montana Burst – Sapphire / Corundum – Ruby, Ceylon, Padparadschah, Pink, Yellow, Green


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

Montana Burst (SAP10.JRG)
By Jeff R. Graham
Copyright 1995
80.2% Light Return
Angles for R.I. = 1.76
57 facets + 8 facets on girdle = 65
8-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.503 T/L = 0.503
P/W = 0.405 C/W = 0.199
H/W = (P+C)/W+0.02 = 0.624
P/H = 0.649 C/H = 0.318
Vol./W^3 = 0.238

Gram Book 1 – I designed this cut for some nice roundish Montana material that I bought. It cuts easy and makes a nice 1ct+ stone. Cut the steps on the crown to your taste, varied widths are better, I think. Cut in refractive index 1.78 to 1.93 (80.1%) with no changes.


Random – Cosine – ISO

Detailed faceting instructions by Jeff Graham available at The Rock Peddler