Achroite and Corundum Physical Properties

Achroite

Corundum

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1 Physical Properties

1.1 Tenacity

Not Available

Brittle

1.2 Solubility

Not Available

insoluble

1.3 Durability

Not Available

1.4 Specific Gravity

2.90-3.403.90-4.05

1 7.18

1.5 Fracture

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

Uneven, Uneven, Gems, Difficult, Fibrous

1.6 Cleavage

Not Available

None – parting in 3 directions

1.7 Mohs Hardness

7-7.59

2 10

1.8 Chemical Composition

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.

Al 2O 3Arthur Thomas , Gemstones (2009)

Achroite and Corundum Chemical Formula

While comparing Achroite and Corundum 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 Achroite and Corundum chemical formula.

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.
Chemical formula of Corundum- Al 2O 3Arthur Thomas , Gemstones (2009)

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Achroite and Corundum Specific Gravity

Another important criteria for qualitative analysis of gemstones is Achroite and Corundum Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Achroite and Corundum Optical Properties during the identification of gemstone. Specific gravity of Achroite is 3.90-4.05 whereas that of Corundum is 3.90-4.05.