|
Jarosite is a basic hydrous sulfate of potassium and iron with a chemical formula of KFe(III)3(OH)6(SO4)2. This mineral is formed in ore deposits by the oxidation of iron sulfides. Jarosite is often produced as a byproduct during the purification and refining of Zinc and is also commonly associated with AMD (acid mine drainage) environments.
Physical Properties
Jarosite is hexagonal and brittle, with basal cleavage, a hardness of 2.5-3.5, and a specific gravity of 3.15-3.26. It is translucent to opaque with a vitreous to dull lustre, and is coloured dark yellow to yellowish-brown. It can sometimes be confused with limonite or goethite with which it commonly occurs in the gossan (oxidized cap over an ore body). Jarosite is an iron analogue of the potassium aluminium sulfate, alunite.
History
Jarosite was first described in 1852 by August Breithaupt in the Barranco del Jaroso in the Sierra Almagrera (near Los Lobos, Cuevas del Almanzora, Almería, Spain). The name jarosite is also directly derived from Jara, the Spanish name of a yellow flower growing in this sierra. The mineral and the flower have the same color.
In 2004 Jarosite was detected on Mars by a Mössbauer spectrometer on the MER-B rover, which has been interpreted as strong evidence that Mars once possessed large amounts of liquid water.
Use in materials science
Jarosite is also a more generic term denoting an extensive family of compounds of the form AM3(OH)6(SO4)2, where A+ = Na, K, Rb, NH4, H3O, Ag, Tl and M3+ = Fe, Cr, V. In condensed matter physics and materials science they are renowned for containing layers with kagome lattice structure, relating to geometrically frustrated magnets[1], [2].
References
- ^ Harrison, A. (2004). "First catch your hare: the design and synthesis of frustrated magnets". J. Phys.: Condens. Matter 16 (9-12): S553–S572. doi:10.1088/0953-8984/16/11/001.
- ^ Wills, A. S. et al. (2000). "Magnetic properties of pure and diamagnetically doped jarosites: Model kagomé antiferromagnets with variable coverage of the magnetic lattice". Phys. Rev. B 61 (9): 6156–6169. doi:10.1103/PhysRevB.61.6156.
External links
| |
