Potassium cyanide (chemical formula: KCN), commonly known as Potassium mountain, is the potash of hydrogen cyanide. In general, potassium cyanide is a solid that is colorless or white, has almond flavour, looks similar to sugar and is soluble in water. Although highly toxic, it is one of the very few substances that can form soluble compounds with elemental gold and is often used for gold plating and polishing of jewellery. It is also sometimes used for gold mining with chemical extraction (although the use of sodium cyanide is more prevalent) and is still used as a rat drug until the 1970 's (English: rodenticide).