The HCO 3 ion in nahcolite's formula is called bicarbonate and is composed of one hydroxide which has taken the place of one of the three oxygens on a normal carbonate ion, CO 3 . Nahcolite was first discovered as a mineral at Searles Lake, California in 1940 and forms several beds in the lake sediments, some up to two feet thick. Nahcolite can absorb water and specimens should be stored in closed containers. Color is colorless, white, brown or gray. Luster is vitreous.
Crystals are transparent to translucent.
Crystal Habits include prismatic crystals, but usually massive crusts. There is a perfect cleavage. Hardness is 2.5. Streak is white. Associated Minerals include other sedimentary evaporite minerals such as hanksite , gaylussite , analcime , halite , pirssonite , northupite , borax and calcite .