
Pitiglianoite is a extremely rare mineral only known worlwide from three localities in Latium and Tuscany. It occurs in this specimen as sharp colorless crystals associated to minoritary afghanite. From: Grosseto, Tuscany, Italy. — Photo: David Hospital · CC BY-SA 4.0
Pitiglianoite
Pitiglianoite is an IMA-recognized mineral species in the silicate class, with the chemical formula K₂Na₆(Si₆Al₆)O₂₄(SO₄)·2H₂O.
It crystallizes in the hexagonal crystal system (space group P6_3). It is a member of the Cancrinite, Cancrinite-sodalite structural group.
Key properties: Mohs hardness 5; specific gravity 2.37; White streak; Vitreous luster; optically uniaxial.
IMA symbol Pgl, IMA status: approved, named in 1990.
Found in metasomatized blocks of volcanic ejecta.
It is found associated with Apatite, diopside, grossular.
The name is derived from the locality at Pitigliano, Italy.