Pure Gold vs K-Gold: Purity, Hallmarks, Uses and Buy-Back
"Pure gold" and "K-gold" are the two most easily confused ideas when buying gold. Both are gold, but they differ in gold content, use and buy-back valuation. Telling them apart helps you buy with clarity and, when selling old gold, judge whether a quote matches the fineness.
What is pure gold?
Pure gold refers to high-fineness gold: 999.9 (four-nines) at about 99.99% and 999 (pure gold / 24K) at 99%+. It has a deep yellow colour and a soft texture, and is used for bars, pellets, traditional jewellery and wedding pieces. Because the gold content is high, its buy-back valuation is usually closest to the pure metal reference price.
What is K-gold?
K-gold is an alloy of gold with other metals (silver, copper, palladium), where "K" denotes the gold-content ratio:
| Mark | Approx. gold content | Common use |
|---|---|---|
| 22K / 916 | 91.6% | Higher-purity but harder jewellery. |
| 18K / 750 | 75% | Most common for set jewellery and fashion pieces. |
| 14K / 585 | 58.5% | Some jewellery and overseas styles. |
| 9K / 375 | 37.5% | Low gold-content K-gold jewellery. |
Adding other metals makes K-gold harder and more wear-resistant, and allows colours like rose or white gold, suiting diamond and gemstone settings.
How to tell them apart: start with hallmarks
Most jewellery carries a hallmark inside — e.g. 999, 916, 750, 585, 375, or 24K, 18K — sometimes with a brand or regional mark. But a hallmark is only an initial reference, not absolute proof; final purity is determined by a jeweller or assay using instruments or touchstone testing.
What differs in buy-back valuation?
- Pure gold: high content, buy-back closest to the pure-metal reference, with relatively simple deductions.
- K-gold: usually valued by actual gold-content ratio (e.g. 18K ≈ 0.75); non-gold parts, set stones and solder points can affect the estimate.
- Craftsmanship rarely recovered: design, brand and workmanship paid at retail are usually not reflected in buy-back.
Use the gold calculator to switch purities and see how the estimated metal value changes for the same weight; the sell-gold net calculator lets you add melt loss and fees for a closer estimate.
Related: Gold as a store of value · Choosing a trustworthy jeweller