This document specifies a gravimetric method for the determination of platinum on a material considered homogeneous. The platinum content of the sample lies preferably between 50 and 999 parts per thousand (‰) by mass. Fineness above 999‰ can be determined using a spectroscopy method by difference (e.g. ISO15093).This method is also intended to be used as one of the recommended methods for the determination of fineness in jewellery alloys covered by ISO 9202.