Goethite and Gahnite Physical Properties
Tenacity
Not Available
Not Available
Solubility
HCl soluble
Not Available
Durability
Not Available
Not Available
Specific Gravity
4.27-4.29
4.00-4.62
Fracture
Uneven, torn surfaces, (e.g. fractured metals)., Uneven, Gemstones (2009), torn surfaces, (e.g. fractured metals).
Conchoidal, Uneven
Cleavage
Perfect {010}
Indistinct parting on [111]
Mohs Hardness
5-5.5
7.5-8
Chemical Composition
FeO(OH)Arthur Thomas , Gemstones (2009)
ZnAl 2O 4Michael OâDonoghue , Gems, Sixth Edition (2006)
Goethite and Gahnite Chemical Formula
While comparing Goethite and Gahnite 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 Goethite and Gahnite chemical formula.
- Chemical formula of Goethite- FeO(OH)Arthur Thomas , Gemstones (2009)
- Chemical formula of Gahnite- ZnAl 2O 4Michael OâDonoghue , Gems, Sixth Edition (2006)
Goethite and Gahnite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Goethite and Gahnite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Goethite and Gahnite Optical Properties during the identification of gemstone. Specific gravity of Goethite is 4.00-4.62 whereas that of Gahnite is 4.00-4.62.