Holmquistite from the Foote Mineral Co., Kings Mountain, North Carolina . Held at the A. E. Seaman Mineral Museum . — Photo: Chris857 · CC BY-SA 3.0
Holmquistite
A rare lithium amphibole forming blue-black orthorhombic prisms up to 10 cm in lithium pegmatites.
Intro adapted from Wikipedia (CC BY-SA).
Holmquistite is an IMA-recognized mineral species in the silicate class, with the chemical formula Li₂(Mg₃Al₂)Si₈O₂₂(OH)₂.
It crystallizes in the orthorhombic crystal system (space group Pnma). It is a member of the Amphibole structural group.
Key properties: Mohs hardness 5–6; specific gravity 2.95–3.13; White, with sky-blue tinge streak; Vitreous luster; optically biaxial.
IMA symbol Hlm, IMA status: approved, named in 1913.
Occurs as metasomatic replacements near the outer margins of lithium-rich pegmatites.
It is found associated with Quartz, clinoholmquistite, tourmaline, spodumene, plagioclase, biotite, clinozoisite, \hornblende.".
The mineral was named to honor the Swedish petrologist, Per Johan Holmquist (1866–1946), of Stockholm.