Alunite
Alunite | ||
---|---|---|
Specific gravity 2.6 – 2.9 | | |
Optical properties | Uniaxial (+) | |
Refractive index | nω = 1.572 nε = 1.592 | |
Birefringence | δ = 0.020 | |
Other characteristics | Strongly pyroelectric
Radioactive 9.44% (K) | |
References | [2][3][4][5][6][7] |
Alunite is a hydroxylated aluminium potassium sulfate mineral, formula KAl3(SO4)2(OH)6. It was first observed in the 15th century at Tolfa, near Rome, where it was mined for the manufacture of alum. First called aluminilite by J.C. Delamétherie in 1797, this name was contracted by François Beudant three decades later to alunite.[8]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/1/1d/Mineraly.sk_-_alunit_m.jpg/220px-Mineraly.sk_-_alunit_m.jpg)
Alunite crystals morphologically are
![](http://upload.wikimedia.org/wikipedia/commons/thumb/7/78/Alunite_Basic_hydrous_aluminum_potassium_sulfate_Marysvale_Piute_County_Utah_2324.jpg/220px-Alunite_Basic_hydrous_aluminum_potassium_sulfate_Marysvale_Piute_County_Utah_2324.jpg)
Sodium can substitute for potassium in the mineral, and when the sodium content is high, is called natroalunite.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/3/39/Alunite_crystal_structure.png/350px-Alunite_crystal_structure.png)
Alunite is an analog of jarosite, where aluminium replaces Fe3+. Alunite occurs as a secondary mineral on iron sulfate ores.
Alunite occurs as veins and replacement masses in
Historically extensive deposits were mined in Tuscany and Hungary, and at Bulahdelah, New South Wales, Australia.[8] It is currently mined at Tolfa, Italy. In the United States it is found in the San Juan district of Colorado; Goldfield, Nevada; the ghost town of Alunite, Utah near Marysvale; and Red Mountain near Patagonia, Arizona. The Arizona occurrence lies appropriately above a canyon named Alum Gulch. Alunite is mined as an ore of both potassium and aluminium at Marysvale.[6] Some of the ore deposits were located by airborne and satellite multispectral imaging.
An article in the May/June 2019 issue of Archaeology magazine states that in China, in Henan province, an assortment of ceramic objects and jars were found, dating back 2000 years. In one of the jars, a mixture of alunite and potassium nitrate was found. The mixture was then thought to be a "mixture of immortality" mentioned in ancient Chinese texts. Obviously, this does not appear to have succeeded.[9]
See also
References
![](http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
- S2CID 235729616.
- ^ http://rruff.geo.arizona.edu/doclib/hom/alunite.pdf Handbook of Mineralogy
- ^ http://www.mindat.org/min-161.html Mindat.org
- ^ http://webmineral.com/data/Alunite.shtml Webmineral data
- ^ "Radioactive Gems : ClassicGems.net".
- ^ ISBN 0-471-80580-7.
- ^ Mineralienatlas
- ^ a b c d public domain: Spencer, Leonard James (1911). "Alunite". In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 1 (11th ed.). Cambridge University Press. p. 773. One or more of the preceding sentences incorporates text from a publication now in the
- ^ Urbanus, Jason. "World Roundup - Archaeology Magazine". www.archaeology.org. Archaeological Institute of America. Retrieved 6 August 2019.
- Hurlbut, Cornelius S. (1966). Dana's Manual of Mineralogy (17th ed.). ISBN 0-471-03288-3.