Meridianiite — MgSO
4•11H
2O — is the crystalline 11-hydrate
magnesium sulfate phase that precipitates from solutions saturated in Mg
2+ and SO
42- ions at temperatures less than 2 °C. Clear to colorless, it is a naturally occurring
mineral species found on
Earth in a variety of environments including sea ice, crusts and efflorescence’s in coal/metal mines, cave systems, oxidized zones of sulfide deposits, salt lakes/playa’s and Antarctic ice-cores. Named for locality data obtained by the NASA
Opportunity Rover at
Meridiani Planum, it has been suggested that mineral
casts present in the Martian sulfate deposits are indicative of this minerals former presence in the area. It is commonly associated with other
evaporite minerals such as
epsomite,
mirabilite,
halides, and other sodium-magnesium-sulfates.