9k · 14k · 18k · 24k — Not All Gold Is Worth the Same

If you’re thinking about selling a piece of jewellery — or simply want to understand what you’ve got tucked away in a drawer — the first thing you need to know is the karat of your piece. It’s the factor that most influences its value, and the difference between a good offer and a bad one often comes down to knowing exactly what kind of gold you have.

What do karats mean?

Karats measure the proportion of pure gold in an alloy. Pure gold is too soft for most jewellery, so it’s mixed with other metals — silver, copper, zinc, palladium — to give it hardness, colour and resistance to everyday wear.

24 karat — 99.9% pure gold

Hallmark: 999. Gold in its purest form. Intense yellow colour, extraordinary shine, but extremely soft. Reserved for bullion, investment coins and some traditional Asian jewellery. In Spain, you rarely find it in everyday rings or bracelets.

18 karat — 75% pure gold

Hallmark: 750. The standard for fine jewellery in Spain and much of Europe. The vast majority of engagement rings, wedding bands, chains and quality earrings sold in Spanish jewellers are 18k. It offers the perfect balance of purity, durability and colour.

14 karat — 58.5% pure gold

Hallmark: 585. The standard in the United States and much of Europe. Harder than 18k, which makes it especially popular for pieces that see heavy daily use. If you have jewellery bought abroad or online, it’s very likely to be 14k.

9 karat — 37.5% pure gold

Hallmark: 375. The minimum level that can legally be called “gold” in many countries. Very common in jewellery from the UK, Ireland and Australia. More affordable pieces, but because they contain less pure gold, their resale value by weight is proportionally lower.

How do you find out what karat your jewellery is?

Look for the hallmark engraved in a discreet spot: the inside of a ring, the clasp of a chain, the back of a pendant. The key numbers: 375 = 9k, 585 = 14k, 750 = 18k, 999 = 24k.

If the hallmark isn’t visible — due to wear, age, or because the piece simply doesn’t carry one — the only reliable way is a professional XRF (X-ray fluorescence) analysis. It’s instant and doesn’t damage the piece at all.

How do karats affect the price?

The calculation is straightforward. If the day’s LBMA price values pure gold at €85 per gram:

• 1 gram of 18k → 85 × 0.75 = €63.75
• 1 gram of 14k → 85 × 0.585 = €49.73
• 1 gram of 9k → 85 × 0.375 = €31.88

The final offer includes a deduction for refining, logistics and shipping insurance costs — but the basis is always: price × weight × purity.

What about the colour of the gold?

Colour doesn’t affect the value by weight. White gold contains palladium or nickel in the alloy; rose gold has a higher proportion of copper. What matters is the karat. An 18k rose-gold ring is worth exactly the same by weight as an 18k yellow-gold one.

Find out the real value of your jewellery

Use our online gold calculator for a quick estimate based on the day’s LBMA price, or read our full guide to how much your gold is really worth. When you want an exact appraisal from a GIA-certified gemologist using XRF analysis equipment, request your free pack.