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پلی هالیت
EntityQ425034· pop 21· linked from 36 articles

پلی هالیت

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Polyhalite is an evaporite mineral, a hydrated sulfate of potassium, calcium and magnesium with formula: . Polyhalite crystallizes in the triclinic system, although crystals are very rare. The normal habit is massive to fibrous. It is typically colorless, white to gray, although it may be brick red due to iron oxide inclusions. It has a Mohs hardness of 3.5 and a specific gravity of 2.8. It is used as a valuable fertilizer.

Key facts

Mineral.name
Polyhalite
Mineral.image
History museum of Truskavets 081.jpg
Mineral.caption
Museum specimen of polyhalite and anhydrite
Mineral.category
Sulfate mineral
Mineral.IMAsymbol
Plhl
Mineral.strunz
7.CC.65
Mineral.system
Triclinic
Mineral.class
Pinacoidal () (same H-M symbol)
Mineral.symmetry
F
Mineral.unit cell
a = 6.95 Å, b = 8.88 Å, c = 6.95 Å; α = 104.06°, β = 113.94°, γ = 101.15°; Z = 4
Mineral.color
Colorless, white, gray; often salmon-pink to brick-red from included iron oxide
Mineral.habit
Typically fibrous, foliated, massive; rarely as tabular crystals; pseudo-orthorhombic
Mineral.twinning
Characteristically polysynthetic on {010}, {100}
Mineral.cleavage
Perfect on {10}; parting on {010}
Mineral.fracture
Conchoidal
Mineral.tenacity
Brittle
Mineral.mohs
3.5
Mineral.luster
Vitreous to resinous

via Wikipedia infobox