Hydroboracite is a hydrated borate mineral (hence the name) of calcium and magnesium, whose chemical composition is CaMgB<sub>6</sub>O<sub>8</sub>(OH)<sub>6</sub>÷3H<sub>2</sub>O. It was discovered in 1834 in the Inder lake, Atyrau Province, Kazakhstan. Hydroboracite is a minor borate ore mineral.