Orthowalpurgite

Formula: (UO₂)Bi₄O₄(AsO₄)₂.2H₂O

Origin of name: from orthorhombic and walpurgite

Crystal system: orthorhombic

Crystal class: 2/m 2/m 2/m

Twinning: 

Unit cell: 

Colour: yellow

Diaphaneity: transparent

Luster: adamantine

Habit: tabular crystals to 0.3 mm in fan-shaped aggregates to 1 mm

Hardness: 4.5

Specific gravity: 6.51

Cleavage: 1; {001} indistinct

Tenacity: 

Streak: pale yellow

Synonyms/varieties:

Comments: dimorphous with walpurgite, soluble in warm dilute HCl