- pearl ash
Wikipedia Article About Potash on Wikipedia
Potash (or carbonate of potash) is an impure form of Potassium carbonate (K2CO3) mixed with other potassium salts. Potash has been used since antiquity in the manufacture of glass and soap, and as a fertilizer. The name comes from the English words pot and ash, referring to its discovery in the water-soluble fraction of wood ash.
It is today principally produced by mining suitable deposits which are found throughout the world.
The term has become somewhat ambiguous due to the substitution in fertilizers of cheaper potassium salts such as potassium chloride (KCl) or potassium oxide (K2O), to which the same common name is now sometimes also applied. In addition, potassium hydroxide (KOH) is commonly called caustic potash, an additional source of confusion.