Angelellite

Formula:  Fe₄(AsO₄)₂O₃

Origin of name:  For Victorio Angelelli (19080 ), Argentine mineralogist, Director of the Argentinian Geological Survey

Crystal system:  Triclinic

Crystal class:  -1

Twinning:

Unit cell: a = 6.461 Å, b = 6.594 Å, c = 5.036 Å, a = 106.21°, b = 98.35°, g = 108.86°

Colour:  Blackish brown

Diaphaneity: Semitransparent

Luster:  Adamantine to submetallic

Habit:  Crystals usually tabular; globular and crystalline incrustations

Hardness:  5.5

Specific gravity:  4.87

Cleavage:  1; {001}

Tenacity: Brittle

Streak:  Reddish brown

Synonyms/varieties:

Comments: Probably of exhalative origin, in tin ore.