Goethite and Black Opal Physical Properties

Goethite

Black Opal

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1 Physical Properties

1.1 Tenacity

Not Available

1.2 Solubility

HCl soluble

Not Available

1.3 Durability

Not Available

1.4 Specific Gravity

4.27-4.291.97-2.22

1 7.18

1.5 Fracture

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

ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)

1.6 Cleavage

Perfect {010}

Not Available

1.7 Mohs Hardness

5-5.56-6.5

2 10

1.8 Chemical Composition

FeO(OH)Arthur Thomas , Gemstones (2009)

SiO 2 + H 2OUlrich Henn and Claudio C.

Goethite and Black Opal Chemical Formula

While comparing Goethite and Black Opal 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 Goethite and Black Opal chemical formula.

Chemical formula of Goethite- FeO(OH)Arthur Thomas , Gemstones (2009)
Chemical formula of Black Opal- SiO 2 + H 2OUlrich Henn and Claudio C.

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Goethite and Black Opal Specific Gravity

Another important criteria for qualitative analysis of gemstones is Goethite and Black Opal Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Goethite and Black Opal Optical Properties during the identification of gemstone. Specific gravity of Goethite is 1.97-2.22 whereas that of Black Opal is 1.97-2.22.