18k gold price per gram

Outside the United States, 18k is what serious jewellery means. Italian, French and most other European manufacturing settles here, and the major houses use it almost exclusively. The hallmark is 750, occasionally written 0.750 or 18K on American and Middle Eastern work.

The reason is colour. At 75% gold the yellow is deep and unmistakably gold rather than the paler tone of 14k. White and rose 18k also read as richer, because there is less base metal available to shift the hue.

This matters more at 18k than at any other purity, because this is where the branded jewellery lives. A Cartier, Bulgari or Tiffany piece in 18k is frequently worth several times its melt value on the second hand market, and a gold buyer weighing it will quote you melt and nothing else. They are not cheating you; they are buying metal. But you would be throwing away the difference.

Look for a maker's mark alongside the 750, and a serial number on the inside of a band or the back of a clasp. If either is present, get a second hand valuation before you get a scrap quote. Even unsigned but well made 18k with good stones is usually worth more intact than melted.

At 75% gold, 18k is noticeably softer than 14k. Rings worn daily thin at the back of the band, prongs wear down and need retipping, and surface scratches accumulate quickly into a satin finish. None of this affects the metal value, since a scratched gram weighs the same, but it does affect whether the piece is worth keeping as jewellery.

It also means an old 18k ring can weigh appreciably less than it did new. If you are comparing a valuation from years ago against today's, weigh it again rather than trusting the old figure.

The arithmetic is straightforward: 0.75 against 0.5833, which is 28.6% more gold in every gram. A 10 gram 18k chain carries 7.5 grams of fine gold where a 10 gram 14k chain carries 5.83. At any spot price the 18k piece is worth just under a third more.

That gap is worth knowing when you are selling a mixed lot. Buyers should weigh and quote each karat separately. If someone offers you one blended price for a bag containing both, they are pricing the whole lot nearer the lower karat, and you should ask them to separate it.