The document specifies a gravimetric method for the determination of platinum in platinum jewellery alloys, preferably within the range of fineness as stated in ISO 9202. Alloys may contain iridium, palladium, rhodium, copper, cobalt, less than 5 % tungsten, gold, ruthenium, gallium, chromium and indium. Some modifications are indicated where palladium, iridium, gold, ruthenium or rhodium are present.