Petalite and Spinel Physical Properties
Tenacity
Brittle
  
Not Available
  
Solubility
insoluble
  
none
  
Durability
Not Available
  
Not Available
  
Specific Gravity
2.40
  
3.64-3.66
  
Fracture
Subconchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal
  
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009)
  
Cleavage
Perfect on {001}, poor on {201} with 38.5° angle between the two
  
None, but may exhibit slight parting
  
Mohs Hardness
6-6.5
  
8
  
Chemical Composition
LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
  
MgAl2O4
  
Petalite and Spinel Chemical Formula
While comparing Petalite and Spinel 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 Spinel chemical formula.
- Chemical formula of Petalite- LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
- Chemical formula of Spinel- MgAl2O4
Petalite and Spinel Specific Gravity
Another important criteria for qualitative analysis of gemstones is Petalite and Spinel Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Petalite and Spinel Optical Properties during the identification of gemstone. Specific gravity of Petalite is 3.64-3.66 whereas that of Spinel is 3.64-3.66.