Zoisite and Sillimanite Physical Properties
Tenacity
Not Available
  
Tough
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
3.20-3.50
  
3.20-3.26
  
Fracture
Uneven, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Even
  
Splintery
  
Cleavage
Perfect {010} imperfect {100}
  
{010} perfect
  
Mohs Hardness
6-7
  
6-7.5
  
Chemical Composition
Ca2Al3(SiO4)3(OH)
  
Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)
  
Zoisite and Sillimanite Chemical Formula
While comparing Zoisite 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 Zoisite and Sillimanite chemical formula.
- Chemical formula of Zoisite- Ca2Al3(SiO4)3(OH)
- Chemical formula of Sillimanite- Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)
Zoisite and Sillimanite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Zoisite and Sillimanite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Zoisite and Sillimanite Optical Properties during the identification of gemstone. Specific gravity of Zoisite is 3.20-3.26 whereas that of Sillimanite is 3.20-3.26.