Chalcomenite

Formula:  CuSeO₃ ^. 2H₂O

Origin of name:  From Greek for copper and moon

Crystal system:  Orthorhombic

Crystal class:  222

Twinning:

Unit cell: a = 6.671 Ǻ, b = 9.193 Ǻ, c = 7.384 Ǻ

Colour:  Bright blue

Diaphaneity:

Luster:  Vitreous

Habit:  Crystals prismatic or acicular, minute

Hardness:  2 to 2.5

Specific gravity:  3.312

Cleavage:  None

Tenacity:

Streak:

Synonyms/varieties:

Comments:  Dimorphous with clinochalcomenite