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}
Mineral.cleavage: Perfect on {001}
Mineral.luster: Vitreous
Mineral.diaphaneity: Transparent
Mineral.mohs: 3.5
Mineral.gravity: 3.295
Mineral.opticalprop: Biaxial (+)

via Wikipedia infobox

Wikidata facts

Image: Acuminite crystal structure (Krogh, Ploug-Sorensen, Leonardsen 1991) along a axis.png

Show 5 more facts

Nickel-Strunz 9th edition (updated 2009): 3.CC.10
Nickel-Strunz '10th ed', review of (9th ed/ 2009 update): 3.CC.10
IMA Mineral Symbol: Acu
chemical formula: SrAlF₄(OH)·H₂O
Commons category: Acuminite

Sources (1)

wikidata.org

via Wikidata · CC0

~1 min read

Article

2 sections

Contents

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.