Uranosphaerite

Formula: Bi₂U₂O₉.3H₂O

Origin of name: from uranium and from Greek for sphere, in allusion to its globular forms

Crystal system: Monoclinic

Crystal class: 2/m

Twinning:

Unit cell: a = 7.559, b = 7.811, c = 7.693, β = 92.88°

Colour: Reddish orange to orange yellow, golden, orange, brick red

Diaphaneity: Semitransparent

Luster: Dull, greasy on fractures

Habit: crystals elongated on c-axis, in globular aggregates to 0.5 mm, botryoidal, radial

Hardness: 2 to 3

Specific gravity: 6.36

Cleavage: 1; {001} good

Tenacity: 

Streak: Yellow, lighter than colour

Synonyms/varieties:

Comments:  Radioactive