Sillimanite and Rock Crystal Physical Properties
Tenacity
Tough
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
3.20-3.26
  
2.65
  
Fracture
Splintery
  
ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001)
  
Cleavage
{010} perfect
  
Not Available
  
Mohs Hardness
6-7.5
  
7
  
Chemical Composition
Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)
  
SiO 2Walter Schumann , Gemstones of the world (2001)
  
Sillimanite and Rock Crystal Chemical Formula
While comparing Sillimanite and Rock Crystal 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 Sillimanite and Rock Crystal chemical formula.
- Chemical formula of Sillimanite- Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)
- Chemical formula of Rock Crystal- SiO 2Walter Schumann , Gemstones of the world (2001)
Sillimanite and Rock Crystal Specific Gravity
Another important criteria for qualitative analysis of gemstones is Sillimanite and Rock Crystal Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Sillimanite and Rock Crystal Optical Properties during the identification of gemstone. Specific gravity of Sillimanite is 2.65 whereas that of Rock Crystal is 2.65.