“A” Dome: Faceting Design Diagram
Detailed information and guide for Faceting Design Diagrams. This facet design is called a " "A" Dome". This works well in any lightly saturated material.
Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)
"A" Dome (DOME8.JRG)
By Jeff R. Graham
89.7% Light Return
Angles for R.I. = 1.62
61 facets + 8 facets on girdle = 69
4-fold, mirror-image symmetry
L/W = 1.000 T/W = 0.473 T/L = 0.473 P/W = 0.405
C/W = 0.240 H/W = (P+C)/W+0.02 = 0.665 P/H = 0.609 C/H = 0.361 Vol./W^3 = 0.247
Addition # 13 - Cut this in refractive indexes 1.62 to 2.14 with no changes. This works well in any lightly saturated material. I designed it for light Afghan nodules.
Detailed faceting instructions by Jeff Graham available at The Rock Peddler
Tourmaline Value, Price, and Jewelry Information
Mint Tourmalines: Gemstones for Our Times
Tourmaline Engagement Ring Stones: the Ultimate Guide
How Do Tourmalines Form?
Creating Ring Mountings for Deep-Cut Gemstones
How Does Topaz Form?
Prosopite Value, Price, and Jewelry Information
Gemstone Doublets, Triplets, and Other Assembled Stones
When you join the IGS community, you get trusted diamond & gemstone information when you need it.
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!