The Mineral epsomite

Epsomite most commonly forms as efflorescence on cave walls from deposition of material from saline springs. It generally is formed in arid regions and in dry caves which protect it from rain and moisture, for otherwise it dissolves. Epsomite may also form efflorescence in tunnels of sulfide mines from the deposition of sulfur and magnesium-rich water during mining operations. Itis not commonly seen in collections, for it lacks appeal, is very fragile, and must be kept in dry areas to prevent it from disintegrating.

Epsomite forms a solid solution series with the following similar sulfates: Morenosite, a hydrous nickel sulfate (NiSO₄ · 7H₂O), and Goslarite, a hydrous zinc sulfate (NiSO₄ · 7H₂O).

Chemical Formula

MgSO₄ · 7H₂O

Color

White, colorless, gray

Crystal System

Orthorhombic

Properties

Streak White

Hardness 2 - 2.5

Transparency Transparent to translucent

Specific Gravity 1.7

Luster Silky, dull

Cleavage Indiscernible

Fracture Conchoidal, earthy

Tenacity Brittle

Other ID Marks 1) Has a bitter, salt-like taste. 2) Soluble in water.

Crystal Habits

Massive, encrusting, globular, stalactitic, acicular, as fibrous groupings, as cotton-like bunches, and as felt-like masses. May occasionally pseudomorph after other minerals such as Glauberite.

3D Crystal Atlas

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Additional Information

Composition Hydrous magnesium sulfate, sometimes with iron replacing some magnesium

In Group Sulfates; Hydrous Sulfates

Striking Features Taste, solubility, and mode of occurrence.

Environment In sedimentary environments inside protected caves, in saline lake deposits, and as a secondary growth in mine tunnels.

Rock Type Sedimentary

Other Names

	Bitter Salt
	Epsom
	Epsom Salt

Uses

Epsomite is an important industrial mineral. It is chiefly used for the production of epsom salts. It is also used in the preparation of pharmaceutical products, for the production of paper and sugar, and as dying material.

Noteworthy Localities

Epsomite was found as crusts produced by thermal springs in Epsom, Surrey, England, which is the locality it is named after. It occurs in certain areas in the Sahara Desert of Africa, the desert of Central Australia, and the Atacama Desert of Chile, where it sometimes forms thick beds.

In the U.S., Epsomite occurs in the saline lake beds on Kruger Mountain, near Oroville, Okanogan Co, Washington, and in the Carlsbad Caverns of New Mexico. Other occurrences are the Kalkar quarry, Santa Cruz Co., California; The Geysers, Sonoma Co., California; the White Caps mine in Manhattan, Nye Co., Nevada; Majuba Hill mine, Pershing Co., Nevada; and Bisbee, Cochise Co., Arizona.

Distingushing Similar Minerals

Epsomite can be distinguished from other minerals by its habit, taste, and mode of occurrence, although it may be confused with Melanterite, which has a greener color and a different taste.

epsomite Photos

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