Låvenite
Låvenite is an IMA-recognized mineral species in the silicate class, with the chemical formula (Na,Ca)₄(Mn²⁺,Fe²⁺)₂(Zr,Ti,Nb)₂(Si₂O₇)₂(O,F)₄.
It crystallizes in the monoclinic crystal system (space group P2_1/a). It is a member of the Wöhlerite structural group.
Key properties: Mohs hardness 5–6; specific gravity 3.4–3.55; Yellow streak; Vitreous to greasy luster; optically biaxial.
IMA symbol Låv, grandfathered status — known before the IMA’s founding, named in 1884.
Found in alkalic rocks and related pegmatites.
It is found associated with Feldspars, nepheline, titanite, ilmenite, apatite, zircon, amphibole, biotite, eudialyte, catapleiite, astrophyllite, rinkite, lorenzenite, aegirine.
The name refers to its occurrence on Lº aven Island, Langesundsfjord, Norway.