Opal and Sillimanite Physical Properties

Opal

Sillimanite

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1 Physical Properties

1.1 Tenacity

BrittleWalter Schumann

Tough

1.2 Solubility

hot salt water

Not Available

1.3 Durability

Not Available

1.4 Specific Gravity

1.98-2.253.20-3.26

1 7.18

1.5 Fracture

Conchoidal, Conchoidal, Gemstones of the world (2001) More from other references, Brittle

Splintery

1.6 Cleavage

None

{010} perfect

1.7 Mohs Hardness

5-6.56-7.5

2 10

1.8 Chemical Composition

SiO₂ · nH₂O

Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)

Opal and Sillimanite Chemical Formula

While comparing Opal and Sillimanite 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 Opal and Sillimanite chemical formula.

Chemical formula of Opal- SiO₂ · nH₂O
Chemical formula of Sillimanite- Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)

Compare Semi Precious Gemstones

Opal Vs Lehsunia

Opal Vs Alexandrite

Opal Vs Amethyst

Opal and Sillimanite Specific Gravity

Another important criteria for qualitative analysis of gemstones is Opal and Sillimanite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Opal and Sillimanite Optical Properties during the identification of gemstone. Specific gravity of Opal is 3.20-3.26 whereas that of Sillimanite is 3.20-3.26.