Astrophyllite and Petalite Physical Properties

Astrophyllite

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

3.2-3.42.40

1 7.18

1.5 Fracture

Uneven, Brittle, Metallic

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

1.6 Cleavage

Perfect on [001] imperfect on [100]

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

1.7 Mohs Hardness

36-6.5

2 10

1.8 Chemical Composition

(K,Na) 3(Fe2+ ,Mn) 7Ti 2Si 8O 24(O,OH) 7Anthony et al , Handbook of mineralogy (2001)

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

Astrophyllite and Petalite Chemical Formula

While comparing Astrophyllite 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 Astrophyllite and Petalite chemical formula.

Chemical formula of Astrophyllite- (K,Na) 3(Fe2+ ,Mn) 7Ti 2Si 8O 24(O,OH) 7Anthony et al , Handbook of mineralogy (2001)
Chemical formula of Petalite- LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references

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Astrophyllite and Petalite Specific Gravity

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