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)
tetragonalrareHalides
Cumengeite
Pb21Cu20Cl42(OH)40
This specimen features sharp, deep azure-blue tetragonal dipyramidal crystals, often twinned, forming attractive clusters. The crystals exhibit a distinct metallic-blue sheen.
Cumengeite Physical Properties
Mohs Hardness
2.5Crystal System
tetragonalLuster
vitreousStreak Color
pale blueCleavage
perfect on {001}Fracture
conchoidalSpecific Gravity
4.75Colors
deep blue, azure blue, indigo blueTransparency
transparentType Locality
Amelia Mine, Santa Rosalía (El Boleo), Boleo District, Municipio de Mulegé, Baja California Sur, MexicoMineral Group
HalidesUses
collector, scientific researchAssociated Minerals
boleite, pseudoboleite, atacamite, gypsum, anglesite, cerussiteRarity
rareGeological Context
Cumengeite is a rare secondary mineral found in the oxidized zone of lead-copper deposits, typically forming under arid conditions. It is often associated with other complex lead-copper halides.
