Black Opal and Spinel Physical Properties

Black Opal

Spinel

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1 Physical Properties

1.1 Tenacity

Not Available

1.2 Solubility

Not Available

none

1.3 Durability

Not Available

1.4 Specific Gravity

1.97-2.22

3.64-3.66

1.5 Fracture

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

Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009)

1.6 Cleavage

Not Available

None, but may exhibit slight parting

1.7 Mohs Hardness

6-6.5

1.8 Chemical Composition

SiO 2 + H 2OUlrich Henn and Claudio C.

MgAl₂O₄

Black Opal and Spinel Chemical Formula

While comparing Black Opal and Spinel 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 Spinel chemical formula.

Chemical formula of Black Opal- SiO 2 + H 2OUlrich Henn and Claudio C.
Chemical formula of Spinel- MgAl₂O₄

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Black Opal and Spinel Specific Gravity

Another important criteria for qualitative analysis of gemstones is Black Opal and Spinel Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Black Opal and Spinel Optical Properties during the identification of gemstone. Specific gravity of Black Opal is 3.64-3.66 whereas that of Spinel is 3.64-3.66.