Black Opal and Petalite Physical Properties
Tenacity
Not Available
Brittle
Solubility
Not Available
insoluble
Durability
Not Available
Not Available
Specific Gravity
1.97-2.22
2.40
Fracture
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Subconchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal
Cleavage
Not Available
Perfect on {001}, poor on {201} with 38.5° angle between the two
Mohs Hardness
6-6.5
6-6.5
Chemical Composition
SiO 2 + H 2OUlrich Henn and Claudio C.
LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Black Opal and Petalite Chemical Formula
While comparing Black Opal and Petalite 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 Petalite chemical formula.
- Chemical formula of Black Opal- SiO 2 + H 2OUlrich Henn and Claudio C.
- Chemical formula of Petalite- LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Black Opal and Petalite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Black Opal and Petalite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Black Opal and Petalite Optical Properties during the identification of gemstone. Specific gravity of Black Opal is 2.40 whereas that of Petalite is 2.40.