Shigaite and Sillimanite Physical Properties
Tenacity
Moderately flexible
  
Tough
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
2.32
  
3.20-3.26
  
Fracture
Flexible Flexible fragments.
  
Splintery
  
Cleavage
Perfect on {0001}
  
{010} perfect
  
Mohs Hardness
2
  
6-7.5
  
Chemical Composition
Not Available
  
Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)
  
Shigaite and Sillimanite Chemical Formula
While comparing Shigaite 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 Shigaite and Sillimanite chemical formula.
>- Chemical formula of Sillimanite- Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)
Shigaite and Sillimanite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Shigaite and Sillimanite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Shigaite and Sillimanite Optical Properties during the identification of gemstone. Specific gravity of Shigaite is 3.20-3.26 whereas that of Sillimanite is 3.20-3.26.