Ammonium chloride is a white crystalline salt that is highly soluble in water. The natural mineral form (similar to ordinary table salt or sodium chloride) is called ‘Sal Ammoniac’ and is commonly found in volcanic areas. Commercially, ammonium chloride is a by-product of something called the ‘Solvay’ process, which produces soda ash. The material we use might not be dug out of a volcano but it's identical to that found in nature. We use ammonium chloride as a thickener to make it easier to use only the recommended amount of product and avoid waste.