Astrophyllite and Goethite Physical Properties

Astrophyllite

Goethite

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1 Physical Properties

1.1 Tenacity

Not Available

1.2 Solubility

Not Available

HCl soluble

1.3 Durability

Not Available

1.4 Specific Gravity

3.2-3.44.27-4.29

1 7.18

1.5 Fracture

Uneven, Brittle, Metallic

Uneven, torn surfaces, (e.g. fractured metals)., Uneven, Gemstones (2009), torn surfaces, (e.g. fractured metals).

1.6 Cleavage

Perfect on [001] imperfect on [100]

Perfect {010}

1.7 Mohs Hardness

35-5.5

2 10

1.8 Chemical Composition

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

FeO(OH)Arthur Thomas , Gemstones (2009)

Astrophyllite and Goethite Chemical Formula

While comparing Astrophyllite and Goethite 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 Goethite 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 Goethite- FeO(OH)Arthur Thomas , Gemstones (2009)

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Astrophyllite and Goethite Specific Gravity

Another important criteria for qualitative analysis of gemstones is Astrophyllite and Goethite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Astrophyllite and Goethite Optical Properties during the identification of gemstone. Specific gravity of Astrophyllite is 4.27-4.29 whereas that of Goethite is 4.27-4.29.