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MgSO4·7H2O A mineral that occurs in clear, needlelike, orthorhombic crystals; commonly, it is massive or fibrous; luster varies from vitreous to milky, hardness is 2-2.5 on Mohs scale, and specific gravity is 1.68; it has a salty bitter taste and is soluble in water. Also known as epsom salt.



(Epsom salt), a mineral of the sulfate class having the molecular formula MgS04-7H20. Epsomite crystallizes in the orthorhombic system, with prismatic or acicular crystals. White or colorless, it has a glassy luster. Epsomite has a hardness of 2 to 2.5 on Mohs’ scale, and it has a density of 1,680 kg/m3. The mineral is soluble in water and has a bitter, salty taste. It is formed by the evaporation of brine from sulfate salt lakes with a high magnesium content. Epsomite has various uses (seeMAGNESIUMSULFATE).

References in periodicals archive ?
This compound has a very low latent heat of fusion, and melts incongruently above 2 [degrees] C to a slurry mixture of 70% (by volume) microcrystalline epsomite (containing the usual 7 water molecules) and 30% liquid water.
While on the subject of epsomite, readers might enjoy taking a look at A.
Epsomite occurred as secondary encrustations where ground water emerged into openings (Loughlin and Koschmann, 1935).
Pentahydrite was reported with epsomite in one analysis and with alunogen in another (Hobbs, 1905; Palache et al.
Associated minerals are: coskrenite-(Ce), zugshunstite-(Ce), melanterite, halotrichite, pickeringite, apjohnite, epsomite and other hydrated sulfates.
Associated minerals are: humnierite, gypsum, epsomite, picromerite, hematite and an unidentified K-Mg-Mn-vanadate.
Associated minerals are: epsomite, members of the "hair salt" family (the most abundant of which is apjohnite), gypsum, jarosite, tschermigite, diadochite and four other new species: levinsonite-(Y), zugshunstite-(Ce), the probable ammonium analogue of slavikite and an iron phosphate.
7 mm wide) embedded within epsomite or "hair salt" or in cavities bounded by these minerals.
A relatively rare secondary mineral, botryogen occurs as thin, orange-yellow crusts up to several square centimeters in area in the Andrassy III section, associated with epsomite, melanterite and copiapite (Szakall et al.
Species confirmed by X-ray diffraction during this study include alstonite, anglesite, ankerite, aragonite, barytocalcite, barite, brochantite, epsomite, harmotome, hydromagnesite, jarosite, marcasite, melanterite, millerite, serpierite, siderite, sulfur and witherite.
Alum Cave Bluff, a Dana locality for apjohnite, epsomite, melanterite and potash alum, has yielded good microcrystals of several rare sulfate minerals, including three new rare-earth sulfates, and is the first North American occurrence of slavikite.
It is possible, since this mineral has been found only in older, mined out stopes, that the epsomite formed after mining activity.