Alunite and Achroite Physical Properties
Tenacity
Brittle
Not Available
Solubility
Soluble
Not Available
Durability
Not Available
Not Available
Specific Gravity
2.6-2.9
2.90-3.40
Fracture
Conchoidal, Uneven
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)
Cleavage
On {0001}, perfect
Not Available
Mohs Hardness
3.5-4
7-7.5
Chemical Composition
KAl3(SO4)2(OH)6
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.
Alunite and Achroite Chemical Formula
While comparing Alunite and Achroite 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 Achroite chemical formula.
- Chemical formula of Alunite- KAl3(SO4)2(OH)6
- 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.
Alunite and Achroite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Alunite and Achroite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Alunite and Achroite Optical Properties during the identification of gemstone. Specific gravity of Alunite is 2.90-3.40 whereas that of Achroite is 2.90-3.40.