Onyx and Ettringite Physical Properties
Tenacity
Not Available
  
Not Available
  
Solubility
Not Available
  
Partially soluble in water
  
Durability
Not Available
  
Not Available
  
Specific Gravity
2.55-2.70
  
1.77
  
Fracture
Not Available
  
Not Available
  
Cleavage
Indiscernible
  
Perfect on {10 1 0}
  
Mohs Hardness
6.5-7
  
2-2.5
  
Chemical Composition
SiO2
  
Ca 6Al 2(SO 4) 3(OH) 12 26H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)
  
Onyx and Ettringite Chemical Formula
While comparing Onyx and Ettringite 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 Onyx and Ettringite chemical formula.
- Chemical formula of Onyx- SiO2
- Chemical formula of Ettringite- Ca 6Al 2(SO 4) 3(OH) 12 26H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)
Onyx and Ettringite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Onyx and Ettringite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Onyx and Ettringite Optical Properties during the identification of gemstone. Specific gravity of Onyx is 1.77 whereas that of Ettringite is 1.77.