Mirabilite

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Mirabilite, also known as "Glauber's salt", is a hydrous sodium sulfate mineral: Na₂SO₄·10H₂O. It is a vitreous, colorless to white monoclinic mineral which forms as an evaporite from sodium sulfate bearing brines. It is found around saline springs and along saline playa lakes. Associated minerals include: gypsum, halite, thenardite, trona, glauberite, and epsomite.

Mirabilite is unstable and quickly de-hydrates in dry air, the prismatic crystals turning into a white powder (Na₂SO₄). Mirabilite is soft with a hardness of 1.5 - 2, and has a low specific gravity of 1.49.

Thenardite (Na₂SO₄) is an orthorhombic anhydrous sodium sulfate mineral found in volcanic caves on Mt. Etna, Italy. Thenardite absorbs water and converts to mirabilite.

Mirabilite is used as a purgative in the traditional Chinese materia medica; in Mandarin it is called máng xiāo.

[edit] References

• Maricopa.edu
• Webmineral
• Mindat
• American Mineralogist - 1917

[edit] External links

• "Mirabilite as a tracer of past evolution of the Aral Sea"