Spinel
Chemical Formula	MgAl2O4
Species	Oxides & Hydroxides
Crystal System	Isometric
Mohs Scale	7-8
Specific Gravity	3.6-4.1
Color	Various, red to blue to mauve. Dark green, brown. Black
Streak	White
Luster	Vitreous
Refractive Index	n = 1.719
Diaphaneity	Transparent, Translucent
Cleavage	None Observed
Fracture	Irregular/Uneven, Splintery, Conchoidal
Crystal Habit：Cubic, octahedral
Geological Setting：As an accessory mineral in igneous rocks, principally basalts, peridotites, kimberlites. In marbles, pegmatites.