Achroite and Black Opal Physical Properties

Achroite

Black Opal

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1 Physical Properties

1.1 Tenacity

Not Available

1.2 Solubility

Not Available

1.3 Durability

Not Available

1.4 Specific Gravity

2.90-3.40

1.97-2.22

1.5 Fracture

Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)

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

1.6 Cleavage

Not Available

1.7 Mohs Hardness

7-7.5

6-6.5

1.8 Chemical Composition

Na(Li 1.5Al 1.5)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012) Formula given for elbaite.

SiO 2 + H 2OUlrich Henn and Claudio C.

Achroite and Black Opal Chemical Formula

While comparing Achroite 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 Achroite and Black Opal chemical formula.

Chemical formula of Achroite- Na(Li 1.5Al 1.5)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012) Formula given for elbaite.
Chemical formula of Black Opal- SiO 2 + H 2OUlrich Henn and Claudio C.

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Achroite and Black Opal Specific Gravity

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