Common Opal and Alexandrite Physical Properties
Tenacity
Not Available
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
1.98-2.50
  
3.69-3.81
  
Fracture
Conchoidal, Conchoidal, Gemstones of the world (2001)
  
Not Available
  
Cleavage
Not Available
  
1,1 ; 3,2.
  
Mohs Hardness
5.5-6.5
  
8.5
  
Chemical Composition
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)
  
BeAl 2 O 4
  
Common Opal and Alexandrite Chemical Formula
While comparing Common Opal and Alexandrite 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 Common Opal and Alexandrite chemical formula.
- Chemical formula of Common Opal- SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)
- Chemical formula of Alexandrite- BeAl 2 O 4
Common Opal and Alexandrite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Common Opal and Alexandrite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Common Opal and Alexandrite Optical Properties during the identification of gemstone. Specific gravity of Common Opal is 3.69-3.81 whereas that of Alexandrite is 3.69-3.81.