Cordierite and Alunite Physical Properties

Cordierite

Alunite

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1 Physical Properties

1.1 Tenacity

Brittle

1.2 Solubility

Not Available

Soluble

1.3 Durability

Not Available

1.4 Specific Gravity

2.57-2.662.6-2.9

1 7.18

1.5 Fracture

Subconchoidal, Conchoidal, Brittle

Conchoidal, Uneven

1.6 Cleavage

Fair on {100}, poor on {001} and {010}

On {0001}, perfect

1.7 Mohs Hardness

7-7.53.5-4

2 10

1.8 Chemical Composition

Mg2Al4Si5O18

KAl3(SO4)2(OH)6

Cordierite and Alunite Chemical Formula

While comparing Cordierite and Alunite 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 Cordierite and Alunite chemical formula.

Chemical formula of Cordierite- Mg2Al4Si5O18
Chemical formula of Alunite- KAl3(SO4)2(OH)6

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Cordierite and Alunite Specific Gravity

Another important criteria for qualitative analysis of gemstones is Cordierite and Alunite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Cordierite and Alunite Optical Properties during the identification of gemstone. Specific gravity of Cordierite is 2.6-2.9 whereas that of Alunite is 2.6-2.9.