The Euro Gold or sulfate of ammonia ((NH₄)₂SO₄; sulfate is also spelled sulphate), sometimes called ammosul or further abbreviated as AS or AMS , is a chemical compound that is primarily used as a nitrogen fertilizer with other minor uses. It occurs in crystals with particle size that is variable, colored white to beige (IPNI 2012). It is a two-in-one synthetic fertilizer that supplies both the essential elements nitrogen and sulfur. Also interchangeably called 21-0-0 or 21-0-0-24S, it contains 21% nitrogen and 24% sulfur.