Riebeckite and Neptunite Physical Properties
Tenacity
Brittle
  
Brittle
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
3.28-3.44
  
3.19-3.23
  
Fracture
Uneven, Splintery, Brittle
  
Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
  
Cleavage
Perfect on {110}, intersecting at 56° and 124°; partings on {100} and {010}
  
{110} good
  
Mohs Hardness
5.0-6.0
  
5-6
  
Chemical Composition
Not Available
  
KNa 2Li(Fe2+ ,Mn2+ ) 2Ti 2Si 8O 24Michael OâDonoghue , Gems, Sixth Edition (2006)
  
Riebeckite and Neptunite Chemical Formula
While comparing Riebeckite and Neptunite 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 Riebeckite and Neptunite chemical formula.
>- Chemical formula of Neptunite- KNa 2Li(Fe2+ ,Mn2+ ) 2Ti 2Si 8O 24Michael OâDonoghue , Gems, Sixth Edition (2006)
Riebeckite and Neptunite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Riebeckite and Neptunite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Riebeckite and Neptunite Optical Properties during the identification of gemstone. Specific gravity of Riebeckite is 3.19-3.23 whereas that of Neptunite is 3.19-3.23.