Achroite and Afghanite Physical Properties
Specific Gravity
2.90-3.40
2.55-2.65
Fracture
Uneven, ConchoidalWalter Schumann
Conchoidal
Cleavage
Indiscernible
Perfect {10 1 0}
Mohs Hardness
7-7.5
5.5-6
Chemical Composition
Na(Li 1.5Al 1.5)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012) Formula given for elbaite.
(Na,Ca,K) 8(Si,Al) 12O 24(SO 4,Cl,CO 3) 3(H 2O)Arthur Thomas , Gemstones (2009)
Achroite and Afghanite Chemical Formula
While comparing Achroite and Afghanite 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 Achroite and Afghanite chemical formula.
- Chemical formula of Achroite- Na(Li 1.5Al 1.5)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012) Formula given for elbaite.
- Chemical formula of Afghanite- (Na,Ca,K) 8(Si,Al) 12O 24(SO 4,Cl,CO 3) 3(H 2O)Arthur Thomas , Gemstones (2009)
Achroite and Afghanite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Achroite and Afghanite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Achroite and Afghanite Optical Properties during the identification of gemstone. Specific gravity of Achroite is 2.55-2.65 whereas that of Afghanite is 2.55-2.65.