2H 2 O , Hydrated Sodium Bicarbonate Carbonate. Other sodium carbonates include gaylussite , natron , pirssonite , northupite , nahcolite and thermonatrite . Trona is probably the most common and well known of these minerals. They are all difficult to tell apart from each other except when good crystal form is present or when optical or X-ray techniques can be used. All may form as efflorescent crusts on the walls of caves and mines or in soils in arid regions.
Color is gray, colorless, white, pale brown or yellowish.
Luster is vitreous. Crystals are transparent to translucent. Crystal Habits include prismatic to blocky crystals, but usually massive, fibrous or columnar. Cleavage is perfect in one direction and poor in two others. Fracture is subconchoidal to uneven.