Magnesium sulfate constituents of evaporitic potassium-magnesium (K-Mg) salts deposits. Bright spots observed by the Dawn Spacecraft in Occator Crater on the dwarf planet Ceres are most consistent with reflected light from magnesium sulfate hexahydrate. Almost all known mineralogical forms of MgSO are hydrates. Epsomite is the natural analogue of "Epsom salt". Another heptahydrate, the copper-containing mineral alpersite (Mg,Cu)SO·7HO, was recently recognized. Both are, however, not the highest known hydrates of MgSO, due to the recent terrestrial find of meridianiite, MgSO·11HO, which is thought to also occur on Mars. Hexahydrite is the next lower (6) hydrate. Three next lower hydrates—pentahydrite, starkeyite, and especially
Magnesium in biology Magnesium in biology Magnesium is an essential element in biological systems. Magnesium occurs typically as the Mg ion. It is an essential mineral nutrient (i.e., element) for life and is present in every cell type in every organism. For example, ATP (adenosine triphosphate), the main source of energy in cells, must bind to a magnesium ion in order to be biologically active. What is called ATP is often actually Mg-ATP. As such, magnesium plays a role in the stability of all polyphosphate compounds in the cells, including those associated with the synthesis of DNA and RNA. Over 300 enzymes require