“B” Oval: Faceting Design Diagram
Information and guide for Faceting Design Diagrams. This facet design is called a " "B" Oval". The P11(G) can be cut in earlier, after cutting the P6(G).
Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)
"B" Oval (TLINE22.JRG)
By Jeff R. Graham
Copyright 1995
82.5% Light Return
Angles for R.I. = 1.62
57 facets + 12 facets on girdle = 69
2-fold, mirror-image symmetry
96 index
L/W = 1.203 T/W = 0.542 T/L = 0.450
P/W = 0.460 C/W = 0.229
H/W = (P+C)/W+0.02 = 0.709
P/H = 0.648 C/H = 0.324
Vol./W^3 = 0.317
Addition # 1 - The P11(G) can be cut in earlier if you want to, after cutting the P6(G).The meet point at the P9 apex is cut off when the P12's are cut. The meet is where the P9's form a "V". Cut in refractive indexes 1.62 to 1.93 with no changes. Light to medium material, 1-6cts.
Random - Cosine - ISO
Detailed faceting instructions by Jeff Graham available at The Rock Peddler
Jeff R. Graham
The late Jeff Graham was a prolific faceter, creator of many original faceting designs, and the author of several highly-regarded instructional faceting books such as Gram Faceting Designs.
Related Articles
Tourmaline Gem, Price, and Jewelry Information
Mint Tourmalines: Gemstones for Our Times
Tourmaline Engagement Rings: the Ultimate Guide
How Do Tourmalines Form?
Latest Articles
21 Pink Gemstones (How Many Do You Know?)
How Does Topaz Form?
Sphene (Titanite) Value, Price, and Jewelry Information
Citrine Buying Guide
Never Stop Learning
When you join the IGS community, you get trusted diamond & gemstone information when you need it.
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!