What is "gaylussite"

Gaylussite \Gay"lus*site`\, n. [Named after Gay-Lussac, the French chemist.] (Min.) A yellowish white, translucent mineral, consisting of the carbonates of lime and soda, with water.

n. (context mineral English) A saline evaporite, consisting of a mixed sodium and calcium carbonate, with the chemical formula sodium₂calcium(carbonoxygen₃)₂'''·'''5water.

Gaylussite is a carbonate mineral, a hydrated sodium calcium carbonate, formula NaCa(CO)·5HO. It occurs as translucent, vitreous white to grey to yellow monoclinic prismatic crystals. It is an unstable mineral which dehydrates in dry air and decomposes in water.

It is formed as an evaporite from alkali lacustrine waters. It also occurs rarely as veinlets in alkalic igneous rocks. It was first described in 1826 for an occurrence in Lagunillas, Merida, Venezuela. It was named for French chemist Joseph Louis Gay-Lussac (1778–1850).

The mineral has been recently reported from drill core in Lonar lake in central India.