Obsidian and Andalusite Physical Properties
Tenacity
Not Available
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
2.35-2.60
  
3.05-3.21
  
Fracture
Conchoidal, ConchoidalWalter Schumann, Conchoidal
  
Uneven, Subconchoidal, Uneven, Subconchoidal, Splintery, UnevenArthur Thomas, Gemstones (2009)
  
Cleavage
Not Available
  
Good on {110}, poor on {100}
  
Mohs Hardness
5-5.5
  
7.5
  
Chemical Composition
Not Available
  
Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
  
Obsidian and Andalusite Chemical Formula
While comparing Obsidian and Andalusite 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 Obsidian and Andalusite chemical formula.
>- Chemical formula of Andalusite- Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
Obsidian and Andalusite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Obsidian and Andalusite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Obsidian and Andalusite Optical Properties during the identification of gemstone. Specific gravity of Obsidian is 3.05-3.21 whereas that of Andalusite is 3.05-3.21.