Mottramite and Sillimanite Physical Properties
Tenacity
Brittle
  
Tough
  
Solubility
Soluble
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
5.9
  
3.20-3.26
  
Fracture
Sub-Conchoidal, Brittle, Metallic
  
Splintery
  
Cleavage
None observed
  
{010} perfect
  
Mohs Hardness
3
  
6-7.5
  
Chemical Composition
Not Available
  
Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)
  
Mottramite and Sillimanite Chemical Formula
While comparing Mottramite 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 Mottramite and Sillimanite chemical formula.
>- Chemical formula of Sillimanite- Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)
Mottramite and Sillimanite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Mottramite and Sillimanite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Mottramite and Sillimanite Optical Properties during the identification of gemstone. Specific gravity of Mottramite is 3.20-3.26 whereas that of Sillimanite is 3.20-3.26.