Color: Light blue to blue-green
Moh’s Hardness: 7.5-8
Refractive index: 1.57-1.60
Critical Angle: 39.87°
Specific Gravity: 2.65-2.75
Fracture: Conchoidal, tough
Heat Sensitivity: Can be, usually not a problem
Birefringence (double refraction): Weak (.006-.009)
Crystal Structure: Hexagonal
Treatments: Aquamarine is often heat treated to reduce the green/blue color and improve the blue color. It is generally safe to assume most rough has been heated.
What I prefer to polishing with: Cerium oxide with a Spectra Ultralap.
Jeff’s Comments: Cuts and polishes like any other Beryl, usually no problems… I like to use a 1200 Nu Bond lap for pre-polish, it makes the polishing stage faster and easier. Orientating on the “c” is slightly better. Watch for silk and lilly pad type of inclusions perpendicular to the “c” axis.
Design Notes: About any design will work well… I prefer a deeper design and often cut Barions…