The Singapore Assay Office (SAO), a division of Singapore Test Services Pte Ltd, is an independent certification body in Singapore that tests and certifies precious metal articles such as gold, silver, platinum and palladium for purity and content. SAO's Assaying and Hallmarking Certification scheme provides the jewellery trade with indispensable expertise in assaying and hallmarking precious metal articles. As part of the certification scheme, precious metal articles are checked and certified for their precious metal content before releasing them for sale. Through our scheme, consumers are assured of the value of their purchase.