Ardennite-(As)
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameArdennite-(As)
Chemical Formula(Mn,Ca)4(Al,Fe)6(AsO4)(SiO4)2(Si2O7)(OH)6
Mohs Hardness6
Crystal Systemorthorhombic
Lustervitreous
Streak Coloryellowish white
Cleavagegood on {001}, poor on {100} and {010}
Fractureuneven
Specific Gravity3.62
Colorsyellow, orange-yellow, brown, reddish-brown
Transparencytranslucent
Type LocalitySalmchâteau, Vielsalm, Belgium (Type Locality)
Mineral GroupSilicates (Sorosilicate)
Usescollector
Associated Mineralsquartz, albite, spessartine, braunite
Rarityrare
Description
This specimen displays ardennite-(As) as a mass of golden-yellow to orange-brown, fibrous or radiating crystals, partially embedded within a white to translucent quartz matrix.
Geological Context
Ardennite-(As) is a rare manganese arsenate sorosilicate mineral found in metamorphosed manganese-rich deposits, often occurring in quartz veins within schist or gneiss.
