Polyhalite and Andalusite Physical Properties

Polyhalite

Andalusite

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Physical Properties

Tenacity

Brittle

Solubility

Soluble

Durability

Specific Gravity

2.783.05-3.21

1 7.18

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Fracture

Conchoidal

Uneven, Subconchoidal, Splintery

Cleavage

Perfect on {10 1 }; parting on {010}

Good on {110}, poor on {100}

Mohs Hardness

3.57.5

2 10

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Chemical Composition

K2Ca2Mg(SO4)4·2H2O

Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references

Polyhalite and Andalusite Chemical Formula

While comparing Polyhalite and Andalusite physical properties, the important data you should know is its chemical composition. Since chemical formula defines the molecular structure of the crystal, most of the physical properties like color, tenacity, solubility are governed by Polyhalite and Andalusite chemical formula.

Chemical formula of Polyhalite- K2Ca2Mg(SO4)4·2H2O
Chemical formula of Andalusite- Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references

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Polyhalite and Andalusite Specific Gravity

Another important criteria for qualitative analysis of gemstones is Polyhalite and Andalusite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Polyhalite and Andalusite Optical Properties during the identification of gemstone. Specific gravity of Polyhalite is 3.05-3.21 whereas that of Andalusite is 3.05-3.21.