Penberthycroftite
Penberthycroftite is an IMA-recognized mineral species in the arsenate class, with the chemical formula [Al₆(AsO₄)₃(OH)₉(H₂O)₅]·8H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: specific gravity 2.18; White streak; Vitreous to pearly luster.
IMA symbol Pbc, IMA status: approved, named in 2015.
Exceptionally rare, in the oxidized zone of a multi-stage, polymetallic hydrothermal deposit.
It is found associated with Arsenopyrite, bettertonite, bulachite, cassiterite, chalcopyrite, chamosite, goethite, liskeardite, pharmacoalumite-pharmacosiderite, scorodite, quartz.
The name refers to the mine that yielded the first specimens.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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