FINE GOLD CONTAMINATION

Fine gold is very rarely contaminated. In a few circumstances even commercially pure gold has caused cracking. In the commercially pure gold cracking is usually caused by reactions with traces of arsenic, antimony or bismuth. These trace elements may be in pure gold that is bought from electronics refiners. It will usually be supplied in grain form. Gold that is in in-house refining may get contaminated with iron. Iron is present in ferrous sulphate, a chemical used to precipitate the gold. It is very important to wash the gold thoroughly with distilled water to remove chlorides and other minerals. When contamination is suspected, a spectrographic analysis should be performed to determine the source.