demantoid Barion cut - faceting styles
demantoid Barion cut - faceting styles

Demantoid Garnet Faceting


Essential information on demantoid faceting / facet garnet. Read up on the cuts, polishes, tips and a detailed guide on demantoids and learn more about it.

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demantoid Barion cut - faceting styles
"Demantoid Garnet," fancy Barion barrel cut, 0.71 cts, Madagascar. © Dan Stair Custom Gemstones. Used with permission.

Demantoid Garnet

Color: Green, Emerald Green
Moh's Hardness: 6.5-7
Refractive Index: 1.88-1.89
Critical Angle: 32.13°
Specific Gravity: 3.82-3.85
Cleavage: Imperfect
Fracture: Subconchoidal
Heat Sensitivity: Yes
Birefringence (double refraction): 0.057
Crystal Structure: Isometric, rhombic, dodecahedron,icositetrahedron

Treatments: Generally none

What I prefer to polishing with: Alumina oxide with a tin lap (scored).

Jeff's Comments: Typically has horse hair type inclusions/needles, seldom over a gram rough (usually 1-3 carats). Rough is hard to find...

Design Notes: Design choice is limited by the small size and inclusions, I generally cut a simple checker board that is as deep as I can cut from the rough.

Melanite - Opaque black variety (Andradite)
Topazolite - lemon/yellow variety of Andradite (similar to Mali Garnets)

Design Links:
Tic Tac - Good for dark material
Smith Bar - Great for any material
Brilliant Pear - Nice in about anything


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.

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