Euchroite
Image: <bdi><a href="https://www.wikidata.org/wiki/Q56247090" class="extiw" title="d:Q56247090"><span title="mineral collector and dealer">Robert M. Lavinsky</span></a></bdi> (CC BY-SA 3.0)
Mineral NameEuchroite
Chemical FormulaCu2(AsO4)(OH)·3H2O
Mohs Hardness3.5
Crystal Systemorthorhombic
Lustervitreous
Streak Colorpale green
Cleavagegood on {010}
Fractureuneven
Specific Gravity3.4
Colorsemerald-green, apple-green, grass-green
Transparencytransparent
Type LocalityCramer Creek Cu deposit, Missoula County, Montana, USA
Mineral GroupArsenates
Usescollector
Associated Mineralsolivenite, malachite, azurite, brochantite
Rarityuncommon
Description
This specimen of Euchroite displays a vibrant emerald-green color and appears translucent, with an irregular, crystalline form. It is backlit, highlighting its rich green hue and internal structure.
Geological Context
Euchroite is a secondary mineral found in the oxidized zones of copper ore deposits. It forms through the alteration of primary copper minerals and arsenic-bearing minerals in the presence of water.
