Uraninite
Chemical Formula	oxide (UO2)
Species	Oxides & Hydroxides
Crystal System	Isometric
Mohs Scale	5-6
Specific Gravity	10.63-10.95
Color	Steel-black to velvet-black, brownish black, pale gray to pale green; in transmitted light, pale green, pale yellow to deep brown
Streak	Brownish black, gray, olive-green
Luster	Greasy, Sub-Metallic, Dull
Diaphaneity	Opaque
Cleavage	Indistinct
Fracture	Irregular/Uneven, Conchoidal
Crystal Habit：Massive, botryoidal, granular. Octahedral crystals uncommon.