Faceting Design Diagram: Delta “T” – Peridot – Olivine, Green, apple green to yellow green


Peridot (Olivine, Green, apple green to yellow green)

Delta “T” (PDOT8.JRG)
By Jeff R. Graham
Copyright 1998
76% Light Return
Angles for R.I. = 1.67
34 facets + 9 facets on girdle = 43
3-fold, mirror-image symmetry
96 index
L/W = 1.053 T/W = 0.611 T/L = 0.580
P/W = 0.487 C/W = 0.223
H/W = (P+C)/W+0.02 = 0.730
P/H = 0.668 C/H = 0.305
Vol./W^3 = 0.249

Addition # 3 – The P3 cuts to center point, when they look like long straight sided rectangles(3) they are right. You may have to fish a little. The rest of this design cuts easy, any material, 1-8cts. Cut in refractive indexes 1.67 to 2.14 (78.6%)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.