Callaghanite

Formula:  Cu₂Mg₂(CO₃)(OH)₆ ^. 2H₂O

Origin of name:  For E. Callaghan, American geologist

Crystal system:  Monoclinic

Crystal class:  2/m

Twinning:

Unit cell:

Colour:  Azure-blue

Diaphaneity:  Transparent

Luster:  Vitreous

Habit:  Crystals minute, pyramidal

Hardness:  3 to 3.5

Specific gravity:  2.71

Cleavage:  2; {111} and {-111} perfect

Tenacity:

Streak:  White

Synonyms/varieties:

Comments: