What Is Platinum and How Does It Compare with Gold?

Platinum is a dense, naturally white precious metal that keeps its colour to the core, needing no plating to stay white. It asks a higher price and repays it with a permanence no plated metal can match, which is why the finest gem-set jewellery, including important sapphire pieces, so often rides in platinum.

What Platinum Is

Platinum is a precious metal in its own right, one of the platinum-group metals alongside palladium and rhodium. It is silvery-white, exceptionally dense, noticeably heavier than gold volume-for-volume, and highly resistant to corrosion and tarnish. Unlike gold, whose colour must be engineered away to make white jewellery, platinum starts white and stays white at any depth of wear.

Purity: Why Pt950

Where gold jewellery spans purities from 375 to 999, platinum is worked at very high fineness: the common jewellery standard is 950 parts per thousand, marked Pt950, with other grades such as 900 also in use. The alloying few per cent, often ruthenium, iridium, copper or cobalt, tunes hardness and casting behaviour. Because the purity system uses parts per thousand rather than karats, a platinum mark reads like a gold fineness stamp but is prefixed Pt; our karat versus fineness guide explains the notation family.

Platinum Versus White Gold

The comparison every ring buyer eventually makes. White gold is a gold alloy whitened with other metals and almost always rhodium-plated; the plating wears and is periodically renewed. Platinum needs no plating, its colour is its own. It is also more ductile in a way that matters for settings: platinum prongs bend rather than snap, and the metal wears by displacement, developing a satiny patina while losing almost no mass over decades.

The costs of those virtues are weight and price. A platinum ring is markedly heavier than the same design in 18K gold, needs more metal by weight, and is more demanding at the bench, all of which typically make the finished piece more expensive, independent of the day's metal markets.

Platinum in Gem-Set Jewellery

For valuable stones, platinum's grip is the attraction. Prongs stay where the setter puts them, resisting the slow loosening that costs stones their security, and the cool white metal flatters sapphires and diamonds alike. High-value engagement and export pieces are routinely offered in platinum for exactly this reason.

Buying Platinum with Confidence

Find the Pt950 (or Pt900) mark, but treat it as you would any purity stamp, a claim to verify. Marking and hallmarking practices vary by country, XRF testing confirms the metal in seconds, and the invoice should state metal, fineness and weight in writing. Priced fairly and documented properly, platinum is as close to a permanent jewellery metal as the trade offers.