Sillimanite and Boulder Opal Physical Properties
Tenacity
Tough
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
3.20-3.26
  
1.98-2.25
  
Fracture
Splintery
  
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
  
Cleavage
{010} perfect
  
Not Available
  
Mohs Hardness
6-7.5
  
5-6.5
  
Chemical Composition
Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)
  
SiO 2 + H 2OUlrich Henn and Claudio C.
  
Sillimanite and Boulder Opal Chemical Formula
While comparing Sillimanite and Boulder Opal 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 Boulder Opal chemical formula.
- Chemical formula of Sillimanite- Al 2SiO 5Michael OâDonoghue , Gems, Sixth Edition (2006)
- Chemical formula of Boulder Opal- SiO 2 + H 2OUlrich Henn and Claudio C.
Sillimanite and Boulder Opal Specific Gravity
Another important criteria for qualitative analysis of gemstones is Sillimanite and Boulder Opal Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Sillimanite and Boulder Opal Optical Properties during the identification of gemstone. Specific gravity of Sillimanite is 1.98-2.25 whereas that of Boulder Opal is 1.98-2.25.