Gemstone	Crystal System	Density	Hardness	Refractive index	Treatments
Agate	microcrystalline	2.66	6.5-7.0	1.544-1.553	dying
Alexandrite	orthorhombic	3.72	8.5	1.746-1.755	dying
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
Chrysoprase	microcrystalline	2.65	7	1.564-1.660	dying
Corundum	trigonal	4.00	9.0	1.762-1.770	none
Demantoid	cubic	3.84	6.5-7.0	1.875	none
Diamond	cubic	3.52	10	2.417	radiation, drilling, fracture filling
Diopside	monoclinic	3.29	5-6	1.675-1.701	none
Emerald	hexagonal	2.72	7.5-8.0	1.746-1.755	dying, fracture filling, oiling
Garnet	cubic	3.40	5.5-6.5	1.700-1.746	none
Jadeite	microcrystalline	3.34	6.5-7.0	1.660-1.680	dying
Malachite	microcrystalline	3.95	3.5-4.0	1.660-1.910	reconstitution
Maw Sit Sit	aggregate	2.5 - 3.5	6.0-7.0	1.52 - 1.74	none
Moldavite	amorphous	2.40	5.50	1.50	none
Nephrite	microcrystalline	2.40	2.95	1.606-1.632	none
Sapphire	hexagonal	4.00	9	1.762-1.770	heat, fracture filling
Spinel	cubic	3.60	8	1.718	none
Tsavorite	cubic	3.84	6.5 - 7	1.73 - 1.75	none
Tourmaline	trigonal	3.06	7.0-7.5	1.624-1.644	heat
Varisite	orthorhombic	2.50	4.0-5.0	1.560-1.590	none