Mendozite

Sulfate mineral

Mendozite

General
Category| Sulfate minerals, alum series
Formula| NaAl(SO4)2·11H2O
IMA symbol| Mz[1]
Strunz classification| 7.CC.15
Dana classification| 29.5.4.1
Crystal system| Monoclinic
Crystal class| Prismatic (2/m)
(same H-M symbol)
Space group| C2/c
Identification
Formula mass| 440.26 g/mol
Color| colorless
Crystal habit| prismatic, pseudo-rhombohedral
Cleavage| {100} good
{001} indistinct
{010} indistinct
Mohs scale hardness| 3
Luster| vitreous
Streak| white
Diaphaneity| transparent to translucent
Density| 1.74 g/cm3
Optical properties| biaxial (-)
Refractive index| nα = 1.449
nβ = 1.461
nγ = 1.463
Birefringence| δ = 0.014
2V angle| 56° (measured)
Solubility| soluble in water
Alters to| tamarugite
References| [2][3][4][5]

Mendozite is a sulfate mineral, one of the alum series, with formula NaAl(SO4)2·11H2O. It is a hydrated form of sodium aluminium sulfate (soda alum).

It was discovered in western Argentina in 1868, probably near San Juan. The exact location has been lost, but was described as "San Juan, near Mendoza", and it is the latter city that give the mineral its name.[3] It occurs in evaporites, presumably from the oxidation of sulfide minerals in the presence of clays.[3] It is very soluble in water, and so can only be found in dry regions: however, in can still effloresce (lose water of crystallisation) in extremely arid climates, altering to tamarugite (the hexahydrate).[4]

## Bibliography

[edit]

* Palache, P.; Berman H.; Frondel, C. (1960). "Dana's System of Mineralogy, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. (Seventh Edition)" John Wiley and Sons, Inc., New York, pp. 469-471.

## References

[edit]

1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320\. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
2. ^ Mineralienatlas
3. ^ a b c Mendozite, WebMineral.com, retrieved 2009-11-28.
4. ^ a b "Mendozite". Mindat.org. Retrieved 2009-11-28..
5. ^ Fang, J. H.; Robinson, P. D. (1972), "Crystal structures and mineral chemistry of double-salt hydrates: II. The crystal structure of mendozite, NaAl(SO4)2·11H2O", American Mineralogist, 57: 1081–88.

This article about a specific sulfate mineral is a stub. You can help Wikipedia by expanding it.

* v
* t
* e

*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template