Epsomite
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Epsomite, Epsom salt, or magnesium sulfate heptahydrate, is a hydrous magnesium sulfate mineral with formula Template:Chem2.
Physical properties
Epsomite crystallizes in the orthorhombic system. The normal form is as massive encrustations, while acicular or fibrous crystals are rarely found. It is colorless to white with tints of yellow, green and pink. It is a soft mineral with variable Mohs hardness around 2.0~2.5, and it has a low specific gravity Template:Nobr<ref name=":0">Template:Cite web</ref>
It is readily soluble in water, and absorbs water from the air. It converts to hexahydrate with the loss of one water molecule and a switch to monoclinic structure.<ref name=":0" />
The epsomite group includes solid solution series with morenosite (Template:Chem·Template:Chem) and goslarite (Template:Chem·Template:Chem).<ref name="Mindat" />Template:Clarification needed
Etymology
It was first systematically described in 1806 for an occurrence near Epsom, Surrey, England, after which it was named.<ref name=":0" /> It has been also referred to as "cave cotton" when in its fibrous form.<ref name=":1" />
Occurrence
Epsomite forms as encrustations or efflorescences on limestone cavern walls and mine timbers and walls, rarely as volcanic fumarole deposits, and as rare beds in evaporite layers such as those found in certain bodies of salt water.<ref name=":0" /><ref>Template:Cite book</ref> It occurs in association with melanterite, gypsum, halotrichite, pickeringite, alunogen, rozenite, and mirabilite.<ref name=HBM/>
Naturally occurring epsomite in caverns can potentially produce particulates of inhalable size, and may contain significant amounts of toxic impurities.<ref name=":1" /><ref>Template:Cite journal</ref>
Uses
Epsom salt is commonly sold as the main ingredient in bath salt, with additives such as glycerin (used as a humectant) and fragrances. The purpose of bath salts is mostly to make the bathing experience more enjoyable and serve as a vehicle for cosmetics, though they are said to improve cleaning and aid in exfoliation.<ref>Template:Cite book</ref>
Research on topical magnesium (for example Epsom salt baths) is very limited.<ref>Template:Cite web</ref> The trade organization 'Epsom Salt Council' recommends bathing 2 or 3 times/week, using Template:Cvt Epsom salts each time.<ref>Template:Cite report</ref>
