Black Opal and Goethite Physical Properties

Black Opal

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

1.97-2.224.27-4.29

1 7.18

1.5 Fracture

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

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

1.6 Cleavage

Not Available

Perfect {010}

1.7 Mohs Hardness

6-6.55-5.5

2 10

1.8 Chemical Composition

SiO 2 + H 2OUlrich Henn and Claudio C.

FeO(OH)Arthur Thomas , Gemstones (2009)

Black Opal and Goethite Chemical Formula

While comparing Black Opal 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 Black Opal and Goethite chemical formula.

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

Compare Blue Gemstones

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Black Opal and Goethite Specific Gravity

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