Devilline
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 NameDevilline
Chemical FormulaCaCu₄(SO₄)₂(OH)₆·3H₂O
Mohs Hardness2.5
Crystal Systemmonoclinic
Lustervitreous
Streak Colorpale greenish blue
Cleavageperfect on {001}
Fractureuneven
Specific Gravity3.1
Colorsemerald green, bluish green, light green
Transparencytranslucent
Type LocalityRichtárová, Staré Hory, Špania Dolina ore belt, Starohorské Mts, Banská Bystrica Region, Slovakia
Mineral GroupSulfates
Usescollector
Associated Mineralsmalachite, azurite, brochantite, chalcopyrite, quartz
Rarityuncommon
Description
This specimen features vibrant emerald green to bluish-green acicular crystals of Devilline forming radiating sprays and tufts, nestled within a light-colored matrix, possibly quartz, with some yellowish granular material.
Geological Context
Devilline is a secondary mineral that forms in the oxidized zones of copper sulfide deposits, typically in arid or semi-arid environments where copper-bearing solutions interact with calcium-rich host rocks.
