hexahydrite

hexahydrite

[‚hek·sə′hī‚drīt]
(mineralogy)
MgSO4·6H2O A white or greenish-white monoclinic mineral composed of hydrous magnesium sulfate.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
According to (http://www.nature.com/nature/journal/v528/n7581/full/nature15754.html) a study published in the journal Nature last December, the appearance of the bright material in the crater is consistent with a type of magnesium sulfate - an inorganic salt - called hexahydrite. These minerals are also found on Earth, occasionally at the rim of salt lakes.
Study authors, led by Andreas Nathues at Max Planck Institute for Solar System Research, GE[micro]ttingen, Germany, write that the bright material is consistent with a type of magnesium sulfate called hexahydrite. A different type of magnesium sulfate is familiar on Earth as Epsom salt.
Lignite Giral samnple 2 Table 1 Mineral matter % present Quartz (Si[O.sub.2]) 1.2 Anorthite 3.0 Diopside 2.5 Maghemite 3.9 Hematite 10.5 Anhydrite 78.4 Hexahydrite 0.5 Total 100.0
Composition and solubility of some common soluble minerals [8] Mineral Compound Solubility, mol/l Calcite CaC[O.sub.3] (calcium carbonate) 0.00014 Gypsum CaS[O.sub.4] x 2[H.sub.2]O 0.0154 (calcium sulphate) -- Ca[Cl.sub.2] x 6[H.sub.2]O 7.38 (calcium chloride) Magnesite MgC[O.sub.3] (magnesium carbonate) 0.001 Hexahydrite MgS[O.sub.4] x 6[H.sub.2]O 4.15 (magnesium sulphate) Epsomite MgS[O.sub.4] x 7[H.sub.2]O 3.07 (magnesium sulphate) Bischofite Mg[Cl.sub.2] x 6[H.sub.2]O 5.84 (magnesium chloride) Washing [Na.sub.2]C[O.sub.3] x 2.77 soda 10[H.sub.2]O (sodium carbonate) Mirabilite NaS[O.sub.4] x 10[H.sub.2]O 1.96 (sodium sulphate) Thenardite NaS[O.sub.4] (sodium sulphate) 3.45 Halite NaCl (sodium chloride) 6.15 Table 2.
(3) For exposure times greater than 1300 hr, primer failure and film delamination correspond to the accumulation of hexahydrite [(MgS[O.sub.4])*6[H.sub.2]O] compound at the interface.
The more acidic salt (i.e., hexahydrite) was identified at the alloy interface where local pH conditions are lower due to anodic polarization conditions.
Early in December, scientists (http://www.jpl.nasa.gov/news/news.php?feature=4785) identified  the bright spots seen in Occator and other areas of Ceres as a type of salt -- magnesium sulfate hexahydrite -- while a second study discovered ammonia-rich clays on Ceres.
Leachates of oil shale samples of the Terzioglu Member contain starkeyite, hexahydrite, dolomite and calcite [7].
(1973) Nickel hexahydrite from Tasmania, Australia.
According the authors of the study, the bright material seems consistent with a type of magnesium sulfate -- an inorganic salt -- called hexahydrite. These minerals are also found on Earth -- occasionally at the rim of salt lakes.
A relatively common and widespread late-stage mineral, gypsum occurs as small vein-fillings, crusts, and rarely as colorless, twinned, prismatic crystals up to 5 mm long, typically associated with goethite, melanterite, jarosite and hexahydrite. From the oxidation zone green, spherical aggregates 2-3 mm in diameter, consisting of acicular gypsum crystals enclosing malachite, have been reported (Koch, 1966).
Hexahydrite occurs as opaque white pseudomorphs and powdery masses after epsomite, which readily re-hydrate to epsomite.