Natron is a naturally occurring mixture of soium carbonate decahydrate (Na2CO3·10H2O, a naturally occurring form of soda ash) and about 17% sodium bicarbonate (Nahcolite, baking soda, NaHCO3) along with small quantities of household salt (halite, sodium chloride) and sodium sulfate. Natron is white to colorless when pure, varying to gray or yellow with impurities. Natron deposits occur naturally as a part of saline lake beds in arid environments. Throughout history, natron has had many practical applications, which still resonate in the wide range of modern uses of its constituent mineral components. In mineralogy, the term natron is the term used for only the prevailing hydrated sodium carbonate (i.e. sodium carbonate decahydrate) found in the historical salt.