Both are gold, but the difference between solid gold and K-gold lies in fineness — the proportion of gold in the alloy. The karat system (K, from “Karat”) divides pure gold into 24 parts; the higher the K number, the greater the gold content. Understanding this conversion will help you avoid losing out whether you’re buying or selling.
How Do You Convert K Numbers to Purity?
Divide the K number by 24 — that’s the gold-content ratio. The three-digit stamps commonly found on jewellery (e.g. 750, 585) express the same fineness as a parts-per-thousand figure:
| Karat | Stamp | Gold Content | Common Name |
|---|---|---|---|
| 24K | 999 / 9999 | 99.9% – 99.99% | Solid gold, ultra-fine gold |
| 22K | 916 | 91.6% | — |
| 18K | 750 / Au750 | 75.0% | K-gold |
| 14K | 585 / Au585 | 58.5% | K-gold |
For example, “18K” means 18/24 = 75% pure gold; the remaining 25% is copper, silver, zinc, or other metals. These alloying metals aren’t “impurities” — they’re deliberately added to change the hardness and colour of the gold.
Solid Gold vs K-Gold — Different Uses
Solid gold (999/9999) has high purity but is soft — it scratches and deforms easily, making it unsuitable for setting gemstones or fine, intricate designs. For this reason, solid gold is primarily used for wealth preservation: gold bars, coins, and traditional jewellery that prizes “substance” (e.g. dragon-and-phoenix bangles, gold chains).
K-gold (22K, 18K, 14K) becomes significantly harder once alloyed, making it durable enough to securely hold diamonds and gemstones and to achieve delicate, three-dimensional designs. Adjusting the alloy mix also produces different colours:
- Yellow gold: gold blended with silver and copper, retaining its golden hue
- White gold: alloyed with palladium, nickel, and other white metals, usually rhodium-plated on the surface
- Rose gold: higher copper content, giving a warm pinkish tone
In short: for preserving wealth, choose solid gold; for everyday wear and gemstone-set jewellery, K-gold is more practical.
Why Is K-Gold Cheaper at Buyback?
Gold buyback values only the gold content — design and craftsmanship carry no value. The basic formula is:
Buyback price ≈ today’s gold price × purity ratio × weight
At the same 10 grams, solid gold is counted at nearly 100%, while 18K is counted at only 75% and 14K at 58.5%. This is why K-gold’s buyback price is noticeably lower than solid gold — it’s not the dealer lowballing you, but simply that the material contains less gold. For jewellery set with gemstones, the stones are typically removed before weighing the gold.
So before selling K-gold, check the stamp on your item (commonly found on the clasp or inner band) and refer to the table above. If the stamp is worn or in doubt, an XRF spectrometer can test the actual fineness on the spot. Feel free to bring your gold items to Hua Bao Gold — we offer free testing and transparent pricing, weighing in front of you and calculating by fineness with no tricks.
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