Opal and Petalite Physical Properties
Tenacity
BrittleWalter Schumann
Brittle
Solubility
hot salt water
insoluble
Durability
Not Available
Not Available
Specific Gravity
1.98-2.25
2.40
Fracture
Conchoidal, Conchoidal, Gemstones of the world (2001) More from other references, Brittle
Subconchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal
Cleavage
None
Perfect on {001}, poor on {201} with 38.5° angle between the two
Mohs Hardness
5-6.5
6-6.5
Chemical Composition
SiO2 · nH2O
LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Opal and Petalite Chemical Formula
While comparing 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 Opal and Petalite chemical formula.
- Chemical formula of Opal- SiO2 · nH2O
- Chemical formula of Petalite- LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Opal and Petalite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Opal and Petalite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Opal and Petalite Optical Properties during the identification of gemstone. Specific gravity of Opal is 2.40 whereas that of Petalite is 2.40.