Mineralpedia Details for Talmessite

Named for its type locality and first noted locality at the Talmessi Mine in the Esfahan Province of Iran. This rare mineral occurs at just a handful of localities as a secondary mineral in the oxidized zone of hydrothermal mineral deposits as an alteration product of realgar, orpiment or copper-nickel arsenides.

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

Formula

Ca₂Mg(AsO₄)₂·2H₂O 

Crystal System

Triclinic 

Luster

Vitreous (Glassy) 

Color

colorless, white, light green 

Streak

white 

Class

Triclinic - Pinacoidal 

Hardness

5 

WebMineral

View Talmessite 

Mindat

View Talmessite 

Pink crystals to 3mm of cobaltoan Talmessite.