Artinite

Formula:  Mg₂(CO)₃(OH)₂ ^. 3H₂O

Origin of name:  For Ettore Artini (1866-1928), Italian mineralogist, University of Milan, Italy

Crystal system:  Monoclinic

Crystal class:  2/m

Twinning:

Unit cell: a = 16.56 Å, b = 3.15 Å, c = 6.22 Å, b = 99.2°

Colour:  White

Diaphaneity: Translucent

Luster:  Vitreous, silky

Habit:  Sprays and crusts of acicular crystals; spherical or flattened aggregates of radiating fibers; fibrous veinlets

Hardness:  2.5

Specific gravity:  2.02 to 2.03

Cleavage:  2; {100} perfect, {001} good

Tenacity:  Brittle

Streak: White

Synonyms/varieties: Cuproartinite (Cu-containing var.)

Comments: Found in low-temperature hydrothermal veins and as crusts in serpentinised ultrabasic rocks.