Spessartite Faceting Information
Spessartite (Garnet)
Color: Orange to red brown
Moh’s Hardness: 7-7.5
Refractive Index: 1.79-1.81
Critical Angle: 33.96°
Specific Gravity: 4.12-4.20
Cleavage: Imperfect
Fracture: Subconchoidal
Heat Sensitivity: Slightly
Birefringence (double refraction): 0.027
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: Most Garnets cut and polish pretty easily (with the exception of a piece with bubbles/flaws) and are really not much of a problem. Pre-polish with a 1200 steel (not Nu Bond, it will leave orange peel) and polish with tin lap.
Design Notes: Most of the orange/brown/red types of Garnet are saturated and I prefer checker boards and bar cut in them. On lighter Grossular Garnets and Mail types of Garnets I prefer a deeper design.
Design Links:
Tic Tac – Good for dark material
Smith Bar – Great for any material
Brilliant Pear – Nice in about anything
About the author
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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