White crystals of the very rare silicate mineral panunzite from the TL in Monte Somma (Monte Somma, Vesuvius, Campania, Italy). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Panunzite
Panunzite is an IMA-recognized mineral species in the silicate class, with the chemical formula K₃Na(AlSiO₄)₄.
It crystallizes in the hexagonal crystal system (space group P6_3). It is a member of the Tridymite-Nepheline structural group.
Key properties: Mohs hardness 5.5; specific gravity 2.59; White streak; Vitreous luster; optically uniaxial.
IMA symbol Pnz, IMA status: approved, named in 1978.
Within cavities of pyroxene-rich ejecta blocks that are part of a recent volcanoclastic deposit.
It is found associated with Nepheline, augite, biotite.
The name refers to Dr. Achille Panunzi, Professor of Chemistry, University of Naples, Naples, Italy, who discovered the ejecta blocks in which the mineral occurs.