Andalusite and Black Opal Physical Properties
Tenacity
Not Available
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
3.05-3.21
  
1.97-2.22
  
Fracture
Uneven, Subconchoidal, Uneven, Subconchoidal, Splintery, UnevenArthur Thomas, Gemstones (2009)
  
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
  
Cleavage
Good on {110}, poor on {100}
  
Not Available
  
Mohs Hardness
7.5
  
6-6.5
  
Chemical Composition
Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
  
SiO 2 + H 2OUlrich Henn and Claudio C.
  
Andalusite and Black Opal Chemical Formula
While comparing Andalusite and Black 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 Andalusite and Black Opal chemical formula.
- Chemical formula of Andalusite- Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
- Chemical formula of Black Opal- SiO 2 + H 2OUlrich Henn and Claudio C.
Andalusite and Black Opal Specific Gravity
Another important criteria for qualitative analysis of gemstones is Andalusite and Black Opal Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Andalusite and Black Opal Optical Properties during the identification of gemstone. Specific gravity of Andalusite is 1.97-2.22 whereas that of Black Opal is 1.97-2.22.