Autunite
Chemical Formula	Ca(UO2)2(PO4)2·10-12H2O
Species	Phosphates
Crystal System	Orthorhombic
Mohs Scale	2
Specific Gravity	3.1-3.2
Color	Lemon-yellow to sulfur-yellow, greenish yellow to pale green; may be dark green to greenish black
Streak	Pale yellow
Luster	Sub-Vitreous, Resinous, Waxy, Pearly
Refractive Index	n = 1.553 - 1.555 n = 1.575 n = 1.577 - 1.578 n = 1.575 n = 1.572
Diaphaneity	Transparent, Translucent
Cleavage	PerfectPerfect on , indistinct on
Fracture	Micaceous
Crystal Habit：Tabular crystals, foliated or scaly aggregates, and in crusts
Geological Setting：In the oxidation zone of uranium bearing rocks, including sandstones, hydrothermal veins, and granitic pegmatites.