Gold karat explained in one line
Karat is a fraction out of 24. 22K means 22 parts gold to 2 parts other metals, which is 91.6% gold. Pure gold is too soft for daily-wear jewellery, so copper, silver and zinc are added for strength and colour — that alloy is what karat measures.
Because the alloy is invisible, two identical-looking chains of the same weight can differ by tens of thousands of rupees in value. Establishing purity is therefore the first step in any honest valuation, before rate or paperwork is discussed.
Gold purity chart
Common karat values and their gold content:
- 24K — 99.9% gold — coins, bars, investment bullion
- 23K — 95.8% gold — high-purity coins
- 22K — 91.6% gold — standard Indian jewellery
- 21K — 87.5% gold — Gulf-market jewellery
- 18K — 75.0% gold — diamond-set and designer jewellery
- 14K — 58.5% gold — export and everyday western jewellery
- 10K — 41.7% gold — durable low-cost jewellery
- 9K — 37.5% gold — minimum karat in several export markets
10K vs 14K vs 18K: what actually changes
Gold content changes, and everything else follows from it. 18K holds three quarters gold, so it has the richest colour of the three and the highest resale value per gram, but it scratches more easily. 14K, at 58.5%, is noticeably harder and a common choice for rings worn daily. 10K, at 41.7%, is the most durable and the palest, and returns the least per gram when sold.
None of these is 'fake' gold — they are simply different alloy ratios. When you sell, the karat determines the multiplier applied to your net weight, which is exactly why an accurate reading matters more than a stamp.
How to test gold purity reliably
There are three methods you will encounter, and only one of them is both accurate and safe for your jewellery.
- XRF spectrometry — precise, non-destructive, results on screen in seconds; used by refiners and hallmarking centres
- Fire assay — the laboratory benchmark, but the sample is destroyed, so it is unsuitable for finished jewellery
- Touchstone and acid — quick and cheap, damages the surface, and the result depends on the tester's judgement
- Home checks (magnet, hallmark stamp, water density) — can flag an obvious fake, cannot establish karat
What hallmarks tell you
A BIS hallmark on Indian jewellery indicates it was assayed at a recognised centre, and newer pieces carry a six-character HUID that ties the item to that assay record. It is a genuinely useful signal and worth looking for when you buy.
It is not a substitute for testing at the point of sale. Stamps wear down, get applied to a clasp rather than the body, and are occasionally imitated. Testing takes seconds and settles the question, so a good buyer will do it whether the piece is stamped or not.
Get a free purity check at CMG
Bring your gold to our Indore MG Road branch or our Ahmedabad Nikol branch, Monday to Saturday, 10 AM to 8 PM. We clean, weigh and XRF test it in front of you and explain the reading — with no expectation that you sell.
If you would rather not travel, book a free doorstep valuation and the same testing happens at home with a portable XRF unit.