acuminite

Also known as IMA1986-038

Acuminite is a rare halide mineral with chemical formula: SrAlF4(OH)·(H2O). Its name comes from the Latin word acumen, meaning "spear point". Its Mohs scale rating is 3.5.

Key facts

Mineral.name: Acuminite
Mineral.category: Halide mineral
Mineral.formula: SrAlF4OH·(H2O)
Mineral.IMAsymbol: Acu
Mineral.strunz: 3.CC.10
Mineral.system: Monoclinic
Mineral.class: Prismatic (2/m) (same H-M symbol)
Mineral.symmetry: C2/c
Mineral.unit cell: a = 13.223, b = 5.175 c = 14.251 [Å]; β = 11.61°; Z = 8
Mineral.color: White
Mineral.habit: Clusters of acute dipyramidal Spearhead shaped crystals
Mineral.twinning: Contact on {100}

Article

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See also
References

{{infobox mineral | name = Acuminite | category = Halide mineral | formula = SrAlF4OH·(H2O) |IMAsymbol=Acu | strunz = 3.CC.10 | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = C2/c | unit cell = a = 13.223, b = 5.175 c = 14.251 [Å]; β = 11.61°; Z = 8 | color = White | habit = Clusters of acute dipyramidal Spearhead shaped crystals | twinning = Contact on {100} | cleavage = Perfect on {001} | luster = Vitreous | diaphaneity = Transparent | mohs = 3.5 | gravity = 3.295 | opticalprop = Biaxial (+) | refractive = nα = 1.451 nβ = 1.453 nγ = 1.462 - 1.463 | references = }} Acuminite is a rare halide mineral with chemical formula: SrAlF4(OH)·(H2O). Its name comes from the Latin word acumen, meaning "spear point". Its Mohs scale rating is 3.5.

Acuminite has only been described from its type locality of the cryolite deposit in Ivigtut, Greenland.