Gemstones beginning with the letter "B"

Gemstone	Crystal System	Density	Hardness	Refractive index	Treatments
Benitoite	hexagonal	3.64	6.0-6.5	1.757-1.804	none
Beryl	hexagonal	2.72	7.5-8.9	1.577-1.583	heat, radiation, fracture filling, oiling
Bloodstone	microcrystalline	2.60	6.5-7.0	1.535-1.539	none