Gold and Metals

The diamond gets the attention, but the metal holds it, shapes it, and decides how the piece wears and lasts. It is also where a buyer is most often quietly misled, because the words used for metal are slippery. Here is what they mean.

Gold, and what karat measures Pure gold is soft, too soft to hold a stone or survive daily wear, so it is mixed with other metals for strength. Karat measures how much of the mix is gold. 18k gold is 75 percent gold (stamped 750), 14k is 58.5 percent (585), and 9k is 37.5 percent (375). Higher karat means more gold, a richer colour, and a higher price, but a slightly softer metal. Lower karat is harder and cheaper, but paler. 18k is the standard for fine jewelry: enough gold to look and feel right, enough alloy to wear well.

The three golds are the same gold Yellow, white, and rose gold are not different metals. They are the same gold, mixed with different alloys. Yellow is closest to gold's natural colour. Rose is alloyed with copper, which lends the pink. White is alloyed paler and then, almost always, plated with rhodium to make it bright white. That last point matters and is rarely mentioned: white gold's bright finish is a plating that wears over years and needs re-applying to stay white. It is normal upkeep, not a fault, but worth knowing before you choose white gold.

Platinum Platinum is naturally white, denser, and more hard-wearing than gold. It does not need plating to stay white, and rather than wearing away it develops a soft patina over time, which some prefer and some have polished off. It costs more than gold, both for the metal and the work, but for a piece worn every day, particularly one holding a significant stone, its durability and steady colour are worth it.

Solid, or only on the surface This is where the most important distinction hides. Solid gold or platinum is the same metal throughout. The look-alikes are not:

• Gold-filled is a layer of gold pressure-bonded over a base metal. More durable than plating, but not solid.
• Vermeil is a layer of gold over sterling silver.
• Gold-plated is a thin layer of gold over base metal, thinner than gold-filled, and it wears through soonest.

All are real in the sense that there is gold on the surface, but none is solid gold, and the difference is large in both value and longevity. A piece should always tell you which it is. If it does not, treat that silence as the answer.

A note on sensitive skin White gold and plated pieces often contain nickel, a common cause of irritation, especially in earrings worn against broken skin. If your skin is sensitive, choose platinum or higher-karat gold, which contain less or none, and be cautious of plated findings.

How to think about it For a piece you will keep and wear often, choose solid metal, and choose 18k gold or platinum for the best balance of beauty and wear. Know that white gold will need occasional re-plating. And whenever a metal is described in soft words, filled, plated, vermeil, tone, read it as a signal that the piece is not solid, and decide with that in mind.