Mineralpedia Details for Callaghanite

Dr. Eugene Callaghan is the namesake of the mineral Callaghanite as the former Director of the New Mexico Bureau of Mines in the United States and for his work on magnesite deposits. Callaghanite is a rare mineral that is found at the type locality at the Premier Chemical mine near Gabbs, Nevada, but also has an additional USA locality in Oklahoma, as well as newer localities in Italy, Germany, and Austria. It occurs disseminated at the type locality in the contact zone of a diorite and a serpentinized dolostone.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/callaghanite.pdf

Formula

Cu₂Mg₂CO₃(OH)₆·2H₂O 

Crystal System

Monoclinic 

Cleavage

Perfect, Perfect, None 

Luster

Vitreous (Glassy) 

Color

azure, violet blue 

Streak

white 

Class

Monoclinic - Prismatic 

Fracture

Brittle - Uneven 

Hardness

3-3.5 

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Mindat

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Excellent blue pyramidal and bypyramidal Callaghanite crystals to 1.5mm with clear bladed Magnesite to 3mm. Ex. Kent England Collection specimen.