Borax

Borax is a hydrated sodium borate, one of the most important boron minerals and a familiar household chemical. It crystallises as soft, pale, prismatic crystals and crusts where boron-rich desert lakes dry up.

Identifying borax

Borax is very soft (2–2.5), light, and colourless to white or grey, with a dull to glassy lustre. Crystals slowly lose water and become chalky white on the surface when exposed to dry air, and it dissolves readily in water.

Where it is found

Borax forms in evaporite deposits in arid basins. The classic source is Death Valley and the deserts of California, where it was hauled out by the famous twenty-mule teams; other major deposits occur in Turkey and Tibet.