Biotite and Andalusite Physical Properties

Biotite

Andalusite

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Physical Properties

Tenacity

Brittle

Solubility

Durability

Specific Gravity

2.7-3.33.05-3.21

1 7.18

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Fracture

Uneven, Even

Uneven, Subconchoidal, Splintery

Cleavage

Perfect on the {001}

Good on {110}, poor on {100}

Mohs Hardness

2.5-3.07.5

2 10

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Chemical Composition

K(Mg,Fe++)3[AlSi3O10(OH,F)2

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

Biotite and Andalusite Chemical Formula

While comparing Biotite 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 Biotite and Andalusite chemical formula.

Chemical formula of Biotite- K(Mg,Fe++)3[AlSi3O10(OH,F)2
Chemical formula of Andalusite- Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references

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Biotite and Andalusite Specific Gravity

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