Meyerhofferite is a hydrated calcium-borate mineral, with a chemical formula that can be generalized as Ca[B3o3(OH)5.H2O] Its crystal system is triclinic-pinacoidal. When pure, it occurs in translucent, prismatic to tabular crystals. Less pure varieties are opaque, off white and form more blocky crystals, which are often intercrossing as seen in this specimen from Furnace Creek in Death Valley, California, USA. It mainly occurs as an alteration product of other more common borate minerals. Actual width of sample is 85 mm.