Almandine Garnet Faceting
Almandine is the most popular amongst the Garnet family. With its widespread around the world, only a small percentage being mined are of gem quality.
Color: Red with a violet tint, red with an orange tint
Moh's Hardness: 7.5
Refractive Index: 1.78-1.81
Critical Angle: 34.18°
Specific Gravity: 3.95-4.20
Fracture: Subconchoidal, can be brittle
Heat Sensitivity: Slightly, but tiny flaws, bubbles and cracks are common and can be aggravated by heat during the dopping process
Birefringence (double refraction): 0.024
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 and AO2.
Design Notes: Most of the red types of Garnet are saturated and I prefer checker boards and bar cuts in them. On lighter Grossular Garnets and Mail types of Garnets I prefer a deeper design.
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