Outstanding dark orange-brown crystals of the rare mineral parsettensite from the type locality in Parsettens, Switzerland (Parsettens Alp, Tinizong, Oberhalbstein Alps, Albula Region, Grisons, Switzerland). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Parsettensite
Parsettensite is an IMA-recognized mineral species in the silicate class, with the chemical formula (K,Na,Ca)₇.₅(Mn,Mg)₄₉Si₇₂O₁₆₈(OH)₅₀·nH₂O.
It crystallizes in the monoclinic crystal system (space group C2/m). It is a member of the Stilpnomelane, Clay structural group.
Key properties: Mohs hardness 1.5; specific gravity 2.59; Submetallic to metallic luster; optically uniaxial.
IMA symbol Psn, grandfathered status — known before the IMA’s founding, named in 1923.
Found in and peripheral to manganese deposits.
It is found associated with Tinzenite, sursassite, piemontite, rhodonite, manganoan calcite, rhodochrosite, quartz, albite, barite (Parsettens Alpe, Italy); quartz, caryopilite.
The name refers to the original locality, Parsettens Alpe, Switzerland.