Arsenuranylite

Formula:  Ca(UO₂)₄(AsO₄)₂(OH)₄^.6H₂O

Origin of name:  From composition arsenic and uranium and probable relation to phosphuranylite

Crystal system:  Orthorhombic

Crystal class:  2/m 2/m 2/m

Twinning:

Unit cell: a = 15.40 Å, b = 17.40 Å, c = 13.768 Å

Colour:  Orange

Diaphaneity: Semi-transparent

Luster: Translucent

Habit:  Fine scales and lichen-like encrustations of elongated crystals

Hardness:  2.5

Specific gravity:  4.25

Cleavage:  1; {001} perfect

Tenacity:

Streak: Light yellow

Synonyms/varieties:

Comments:  Radioactive. Formed in the oxidised zone of uranium deposits containing arsenic-bearing sulphides.