Classification	Gems														Jewelry-ornamental stones
Hardness classification	I order					II order						III order			I order			II order
Name of material	Diamond	Moissanite	Sapphire(Ruby)	Alexandrite	Exitonit	Spinel	Topaz	Emerald(Aquamarine)	Tourmaline	Zicron	Fianit	Amethyst	Citrine	Garnet	Nanosital	Rhinestone	Swarovski stones	Quartz	Agate
Chemical formula	C	SiC	AI2O3	AI2BeO4	Y3AI5O12	MgAI2O4	AI2[SiO4](f,OH)2	Be3AI2Si6O18	Na(Li,AI)3AI6[(OH)4|(BO3)3Si6O18)	ZrSiO4	ZrO2	SiO2	SiO2	(R^2+)3(R^3+)2[SiO4]3	SiO2:AI2O3	SiO2	SiO2	SiO2	SiO2
Mohs hardness	10.0	9.5	9.0	8.5	8.5	8.0	8.0	8.0	7.5	7.5	7.5	7.0	7.0	7.0	6.5-7.0	7.0	7.0	7.0	6.5
Material density, g/cm^3	3.47-3.55	3.21	3.95-4.00	3.50-3.84	4.56	3.57-3.72	3.49-3.57	2.67-2.71	3.02-3.26	4.60-4.70	6.5-10	2.36-2.65	2.65	3.47-3.83	3.2-3.4	2.6	2.6	2.6	2.6
Refractive index	2.417-2.419	2.654-2.967	1.766-1.774	1.744-1.758	1.833	1.71-1.76	1.606-1.638	1.577-1.583	1.61-1.652	1.81-2.024	2.15-2.25	1.543-1.554	1.544	1.73-1.90	1.65-1.70	1.544	1.544	1.544	1.544
Dispersion	0.044	0.104	0.018	0.015	0.028	0.026	0.014	0.014	0.017	0.039	0.06	0.013	0.013	0.022	0.015	0.013	0.013	0.013	0.013
Birefringence	not	yes	yes	yes	not	not	yes	yes	yes	yes	yes	yes	yes	yes	yes	yes	yes	yes	yes
Resistance t > 800C	not	yes	yes	yes	yes	not	not	not	not	not	not	not	not	not	yes	not	not	not	not