Spinel and Sillimanite Physical Properties
Tenacity
Not Available
  
Tough
  
Solubility
none
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
3.64-3.66
  
3.20-3.26
  
Fracture
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009)
  
Splintery
  
Cleavage
None, but may exhibit slight parting
  
{010} perfect
  
Mohs Hardness
8
  
6-7.5
  
Chemical Composition
MgAl2O4
  
Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)
  
Spinel and Sillimanite Chemical Formula
While comparing Spinel 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 Spinel and Sillimanite chemical formula.
- Chemical formula of Spinel- MgAl2O4
- Chemical formula of Sillimanite- Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)
Spinel and Sillimanite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Spinel and Sillimanite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Spinel and Sillimanite Optical Properties during the identification of gemstone. Specific gravity of Spinel is 3.20-3.26 whereas that of Sillimanite is 3.20-3.26.