Faceting Design Diagram: Bygone – Feldspar – Bytonite, Labradorite, Spectrolite, Orthoclase


Sunstone (Feldspar, Bytonite, Labradorite, Spectrolite, Orthoclase)

Bygone Jeff Graham Facet Design

Bygone Jeff Graham Facet Design

Bygone (SUN18.JRG)
By Jeff R. Graham
Copyright 2006
77.3% Light Return
Angles for R.I. = 1.54
55 facets + 6 facets on girdle = 61
6-fold, mirror-image symmetry
96 index
L/W = 1.155 T/W = 0.524 T/L = 0.454 P/W = 0.704
C/W = 0.194 H/W = (P+C)/W+0.02 = 0.918 P/H = 0.767 C/H = 0.211 Vol./W^3 = 0.411

Addition # 11 – Cut in refractive indexes 1.54 to 2.14 with no changes. This is for light colored materials (no shiller) and it is killer in Beryl. This is pretty easy to cut. It may require a custom setting because of the depth. Note: The girdle can be cut in first and the P1 cut to meet so that center point is not needed and it saves rough.

Bygone Jeff Graham Facet Design

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.