Faceting Design Diagram: Line Point Triangle – Spinel – Red, Pink, Lavender, Green, Blue, Orange, Violet


Spinel (Red, Pink, Lavender, Green, Blue, Orange, Violet)

Line Point Triangle (SPINEL1.JRG)
By Jeff R. Graham
Copyright 1995
87.2% Light Return
Angles for R.I. = 1.71
31 facets + 12 facets on girdle = 43
3-fold, mirror-image symmetry
96 index
L/W = 1.104 T/W = 0.496 T/L = 0.449
P/W = 0.481 C/W = 0.188
H/W = (P+C)/W+0.02 = 0.689
P/H = 0.698 C/H = 0.273
Vol./W^3 = 0.211

Addition # 2 – This triangle cuts easily and makes a nice stone in about any type of material, 1/2-4cts. I like it in light colored Garnet and Sapphire. Cut in refractive indexes 1.71 to 2.14 with no changes. This design is deceptive, it is really quite nice.


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.