Alunite and Alexandrite Physical Properties

Alunite

Alexandrite

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1 Physical Properties

1.1 Tenacity

Brittle

Not Available

1.2 Solubility

Soluble

Not Available

1.3 Durability

Not Available

1.4 Specific Gravity

2.6-2.9

3.69-3.81

1.5 Fracture

Conchoidal, Uneven

Not Available

1.6 Cleavage

On {0001}, perfect

1,1 ; 3,2.

1.7 Mohs Hardness

3.5-4

8.5

1.8 Chemical Composition

KAl3(SO4)2(OH)6

BeAl ₂ O ₄

Alunite and Alexandrite Chemical Formula

While comparing Alunite and Alexandrite 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 Alunite and Alexandrite chemical formula.

Chemical formula of Alunite- KAl3(SO4)2(OH)6
Chemical formula of Alexandrite- BeAl ₂ O ₄

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Alunite and Alexandrite Specific Gravity

Another important criteria for qualitative analysis of gemstones is Alunite and Alexandrite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Alunite and Alexandrite Optical Properties during the identification of gemstone. Specific gravity of Alunite is 3.69-3.81 whereas that of Alexandrite is 3.69-3.81.