Achroite and Petalite Physical Properties

Achroite

Petalite

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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

2.90-3.402.40

1 7.18

1.5 Fracture

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

Subconchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal

1.6 Cleavage

Not Available

Perfect on {001}, poor on {201} with 38.5° angle between the two

1.7 Mohs Hardness

7-7.56-6.5

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.

LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references

Achroite and Petalite Chemical Formula

While comparing Achroite and Petalite 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 Petalite 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 Petalite- LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references

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Achroite and Petalite Specific Gravity

Another important criteria for qualitative analysis of gemstones is Achroite and Petalite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Achroite and Petalite Optical Properties during the identification of gemstone. Specific gravity of Achroite is 2.40 whereas that of Petalite is 2.40.