Petalite and Topaz Physical Properties
Tenacity
Brittle
  
Not Available
  
Solubility
insoluble
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
2.40
  
3.49-3.57
  
Fracture
Subconchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal
  
Subconchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle
  
Cleavage
Perfect on {001}, poor on {201} with 38.5° angle between the two
  
[001] Perfect
  
Mohs Hardness
6-6.5
  
8
  
Chemical Composition
LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
  
Al2SiO4(F,OH)2
  
Petalite and Topaz Chemical Formula
While comparing Petalite and Topaz 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 Petalite and Topaz chemical formula.
- Chemical formula of Petalite- LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
- Chemical formula of Topaz- Al2SiO4(F,OH)2
Petalite and Topaz Specific Gravity
Another important criteria for qualitative analysis of gemstones is Petalite and Topaz Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Petalite and Topaz Optical Properties during the identification of gemstone. Specific gravity of Petalite is 3.49-3.57 whereas that of Topaz is 3.49-3.57.