The Evolution of Platinum Jewellery Alloys: From the 1920s to the 2020s

Abstract

Platinum has only been known to Europe since the 16th century. This was impure platinum, found as grains of native metal in alluvial deposits and comprising mainly platinum alloyed with the other 5 platinum group metals. They were exploited by pre-Colombian Indians of Ecuador and Colombia. In more recent times, the use of platinum in jewellery dates from the late 19th/early 20th century, often as a basis for diamond (and other precious gemstone) jewellery. Early jewellery alloys tended to be based on the existing industrial alloys and comparatively little development of specific jewellery alloys was carried out. Its acceptance as a hallmarkable jewellery metal came in 1975 when, with a wider availability of the metal, platinum was promoted as a high value jewellery metal and platinum jewellery started to grow in popularity, mainly at 950 and 900 fineness qualities. Since that time there has been alloy development specifically for jewellery application and tailored to the requirements of different manufacturing technologies. This review examines the evolution of platinum jewellery alloys over the last century against the challenges presented in developing improved alloys for jewellery application. There has been a substantial increase in alloy development over the last 30 years, particularly focused on improved investment (lost wax) casting alloys as well as better mechanical properties.