Pinalite
A rare lead tungstate-chloride crystallizing in the orthorhombic system.
Intro adapted from Wikipedia (CC BY-SA).
Pinalite is an IMA-recognized mineral species in the tungstate class, with the chemical formula Pb₃(WO₄)OCl₂.
It crystallizes in the orthorhombic crystal system (space group Amam).
Key properties: specific gravity 7.78; Adamantine luster; refractive index 2.497; optically biaxial.
IMA symbol Pnl, IMA status: approved, named in 1988.
A late-stage secondary mineral in the oxidized zone of a base-metal deposit.
It is found associated with Chromian leadhillite, cerussite, matlockite, diaboleite, caledonite, connellite, iranite, murdochite, fluorite, quartz.
The name refers to Pinal Co., Arizona, USA (in turn named for the Pinal Indians), where the mineral was first noted to occur.