Alunite and Spinel Physical Properties

Alunite

Spinel

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1 Physical Properties

1.1 Tenacity

Brittle

Not Available

1.2 Solubility

Soluble

none

1.3 Durability

Not Available

1.4 Specific Gravity

2.6-2.93.64-3.66

1 7.18

1.5 Fracture

Conchoidal, Uneven

Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009)

1.6 Cleavage

On {0001}, perfect

None, but may exhibit slight parting

1.7 Mohs Hardness

3.5-48

2 10

1.8 Chemical Composition

KAl3(SO4)2(OH)6

MgAl₂O₄

Alunite and Spinel Chemical Formula

While comparing Alunite and Spinel 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 Spinel chemical formula.

Chemical formula of Alunite- KAl3(SO4)2(OH)6
Chemical formula of Spinel- MgAl₂O₄

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Alunite and Spinel Specific Gravity

Another important criteria for qualitative analysis of gemstones is Alunite and Spinel Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Alunite and Spinel Optical Properties during the identification of gemstone. Specific gravity of Alunite is 3.64-3.66 whereas that of Spinel is 3.64-3.66.