White platinum dethrones rhodium, the innovation of STS

At the 2021 EPHJ trade show, which is attended by a large majority of the suppliers to the watchmaking industry, the Exhibitors’ Grand Prize was unanimously awarded to the new white platinum coating developed by STS company. This is set to replace the traditional rhodium, the cost of which has rocketed.

The price of rhodium is soaring. Its cost has quadrupled over the past four years and in 2020 it became the world’s most expensive metal, selling for as much as CHF 800 per gram – CHF 80,000 per kilo. And for many reasons it is unlikely to stop there. Mined mostly in South Africa and the Russian Urals, production is no more than 20 tonnes a year, and deposits are inexorably diminishing.

At the same time, demand for rhodium is exploding, mainly because of new anti-pollution measures for cars – catalytic converters, for example. But it is a crucial component in other sectors too, for the nuclear industry, for lighting, mirrors, connectivity technology and more.

The watchmaking sector is also a big user of rhodium. The whitest precious metal after silver, it is highly resistant to corrosion and does not tarnish. Fine coatings of it have been used since time immemorial to reinforce certain crucial parts of the movement – such as the ébauches – to which it gives a highly appreciated white finish.

Discover the complete article written by Pierre Maillard and published in Europastar Première, by clicking here.