White crystals of the rare Pb sulphate mineral sundiusite from the TL in Langban (Långban, Filipstad, Värmland County, Sweden) and only one of the three known localities worldwide. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Sundiusite
Sundiusite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Pb₁₀(SO₄)O₈Cl₂.
It crystallizes in the monoclinic crystal system.
Key properties: Mohs hardness 3; specific gravity 7; White streak; Adamantine luster; optically biaxial.
IMA symbol Sun, IMA status: approved, named in 1979.
On fracture surfaces in a museum specimen of manganese ore from a metamorphosed Fe–Mn orebody.
It is found associated with Blixite, braunite, hausmannite, manganoan biotite, calcite.
The mineral was named to honor Nils Sundius (1886–1976), Swedish mineralogist, who made numerous contributions to Långban mineralogy.