Corundum and Achroite Physical Properties

Corundum

Achroite

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1 Physical Properties

1.1 Tenacity

Brittle

Not Available

1.2 Solubility

insoluble

Not Available

1.3 Durability

Not Available

1.4 Specific Gravity

3.90-4.052.90-3.40

1 7.18

1.5 Fracture

Uneven, Uneven, Gems, Difficult, Fibrous

Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)

1.6 Cleavage

None – parting in 3 directions

Not Available

1.7 Mohs Hardness

97-7.5

2 10

1.8 Chemical Composition

Al 2O 3Arthur Thomas , Gemstones (2009)

Na(Li 1.5Al 1.5)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012) Formula given for elbaite.

Corundum and Achroite Chemical Formula

While comparing Corundum and Achroite 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 Corundum and Achroite chemical formula.

Chemical formula of Corundum- Al 2O 3Arthur Thomas , Gemstones (2009)
Chemical formula of Achroite- Na(Li 1.5Al 1.5)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012) Formula given for elbaite.

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Corundum and Achroite Specific Gravity

Another important criteria for qualitative analysis of gemstones is Corundum and Achroite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Corundum and Achroite Optical Properties during the identification of gemstone. Specific gravity of Corundum is 2.90-3.40 whereas that of Achroite is 2.90-3.40.