IGS Background

Royal Mine: Faceting Design Diagram


Detailed information and guide on Faceting Designs. A Faceting Design Diagram by Jeff R. Graham that presents various cuts, this one is called "Royal Mine".

By Jeff R. Graham, updated on

Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)

Royal Mine (CHECK63.JRG)
By Jeff R. Graham
Copyright 2003
87.4% Light Return
Angles for R.I. = 1.62
61 facets + 8 facets on girdle = 69
4-fold, mirror-image symmetry
96 index
L/W = 1.000 T/W = 0.372
T/L = 0.372 P/W = 0.441 C/W = 0.182
H/W = (P+C)/W+0.02 = 0.643
P/H = 0.686 C/H = 0.282
Vol./W^3 = 0.234

Addition # 8 - This one is really neat. I have always liked an antique/mine cut and this one with a diamond top is cool. Cut in refractive indexes 1.62 to 2.14 (89.7%) with no changes. This works in about any material.


Random - Cosine - ISO

Detailed faceting instructions by Jeff Graham available at The Rock Peddler

Never Stop Learning

When you join the IGS community, you get trusted diamond & gemstone information when you need it.

Become a Member

Get Gemology Insights

Get started with the International Gem Society’s free guide to gemstone identification. Join our weekly newsletter & get a free copy of the Gem ID Checklist!