What is "mirabilite"

Mirabilite \Mi*rab"i*lite\, n. (Min.) Native sodium sulphate; Glauber's salt.

n. (context mineralogy English) A saline evaporite, consisting of sodium sulphate, with the chemical formula sodium₂sulfuroxygen₄'''·'''10water.

Mirabilite, also known as Glauber's salt, is a hydrous sodium sulfate mineral with the chemical formula NaSO·10HO. It is a vitreous, colorless to white monoclinic mineral that 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 dehydrates in dry air, the prismatic crystals turning into a white powder, thenardite (NaSO). In turn, thenardite can also absorb water and converts to mirabilite.

Mirabilite is used as a purgative in the Traditional Chinese medicine; in Mandarin, it is called máng xiāo. Its name is based on the phrase "Sal mirabilis" (Latin for "wonderful salt") used by Johann Rudolph Glauber when he inadvertently synthesized mirabilite.