Alunite and Afghanite Physical Properties
Tenacity
Brittle
Not Available
Solubility
Soluble
Not Available
Durability
Not Available
Not Available
Specific Gravity
2.6-2.9
2.55-2.65
Fracture
Conchoidal, Uneven
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle, Conchoidal, Brittle
Cleavage
On {0001}, perfect
Perfect {10 1 0}
Mohs Hardness
3.5-4
5.5-6
Chemical Composition
KAl3(SO4)2(OH)6
(Na,Ca,K) 8(Si,Al) 12O 24(SO 4,Cl,CO 3) 3(H 2O)Arthur Thomas , Gemstones (2009)
Alunite and Afghanite Chemical Formula
While comparing Alunite 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 Alunite and Afghanite chemical formula.
- Chemical formula of Alunite- KAl3(SO4)2(OH)6
- Chemical formula of Afghanite- (Na,Ca,K) 8(Si,Al) 12O 24(SO 4,Cl,CO 3) 3(H 2O)Arthur Thomas , Gemstones (2009)
Alunite and Afghanite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Alunite and Afghanite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Alunite and Afghanite Optical Properties during the identification of gemstone. Specific gravity of Alunite is 2.55-2.65 whereas that of Afghanite is 2.55-2.65.