How To Check Gold Purity? A Simple Buyer's Guide

Buying gold in India runs on trust. You hand over real money for a metal whose purity you can't see with your eyes. So the only sensible question is the one you're already asking: how do I know this gold is actually as pure as the seller says?

We've manufactured and exported certified gold jewellery since 1996, and we hallmark every piece we sell. So this guide is the same check we'd run ourselves. Here's the good news: India now has a system that takes most of the guesswork out of it. For the small bits it doesn't cover, there are reliable methods, plus a few popular "tricks" you should ignore.

Let's break it down.

What gold purity actually means

Gold purity is the share of pure gold in a piece, measured in karats (K). Pure gold is 24K, or 99.9% gold. Anything below 24K is gold mixed with other metals like silver, copper, and zinc, and the karat number tells you the exact ratio.

The reason jewellery isn't 24K: pure gold is soft. Too soft to hold a diamond, survive daily wear, or keep its shape. So 22K, 18K, and 14K gold trade a little purity for the strength a wearable piece needs. The higher the karat, the more gold, the softer the piece, and the higher the price.

Read more: https://kamajewelry.com/blogs/insights/gold-purity-9k-14k-18k-22k-24k

Gold karat chart

Karat	Gold content	Fineness mark
24K	99.9%	999
22K	91.6%	916
18K	75.0%	750
14K	58.5%	585
9K	37.5%	375

That "fineness" number is the same purity shown in parts per thousand, and it's exactly what gets stamped on your jewellery. So 916 means 91.6% pure, which is 22K.

A quick note: you may see "23K" or "20K" mentioned online as common types. These aren't the grades India actually certifies. According to the Bureau of Indian Standards (BIS), hallmarked gold grades are 24K, 22K, 20K, 18K, 14K, and, since July 2025, 9K. Stick to what's hallmarked.

The fastest way to check: read the BIS hallmark

In India, you don't need to guess gold purity anymore. The Bureau of Indian Standards made hallmarking mandatory for gold jewellery in June 2021, and selling non-hallmarked gold in covered districts is now illegal, with penalties up to five times the value of the article.

So before any home test, do this first: look at the marks stamped on the piece. Every hallmarked gold item must carry three things.

• The BIS logo - a small triangle. This confirms the piece was certified under the official government scheme.
• The purity mark - the three-digit fineness number like 916, 750, or 585. This tells you the karat.
• The HUID code - a six-character alphanumeric code unique to that single piece.

Since 31 March 2023, gold jewellery without a HUID code cannot legally be sold in India. If any of these three marks is missing or unclear, ask the jeweller before you buy.

How to verify the HUID (the step most people skip)

The hallmark stamp is good. The real power is that you can check it yourself, online, in under a minute. We do this with our own pieces, and any buyer can do the same:

1. Download the BIS Care app (free, on Android and iOS).
2. Open it and tap Verify HUID.
3. Enter the six-character code stamped on your jewellery.
4. The app shows the registered jeweller, the assaying centre that tested it, and the certified purity.

If the details in the app match the piece in your hand, you're holding genuine, certified gold. If anything doesn't match, walk away. This single check beats every home test combined.

Home tests: which ones work, which ones don't

You've probably seen the magnet, vinegar, and float tests passed around as easy ways to spot fake gold. Be careful here. These tests can only catch obvious, low-effort fakes. They cannot tell you whether something is 22K or 18K, and they can be fooled by gold-plated items. Treat them as a rough first look, never as proof.

Tests with some value

• Magnet test. Real gold is not magnetic. If a magnet pulls the piece, it contains a lot of other metals. But passing this test doesn't prove purity, since many fake metals aren't magnetic either.
• Weight and feel. Gold is dense and heavy for its size. A piece that feels suspiciously light for how big it looks is worth questioning.

Tests to ignore

• Vinegar and float tests. These are unreliable. Plenty of genuine gold behaves differently than the "rule" claims, and plenty of fakes pass. Don't make a buying decision on them.

Bottom line: home tests are a quick sniff check, not a verdict.

When you want a professional answer

If you're buying something expensive, selling old gold, or just want certainty, get it tested at a BIS-recognised Assaying and Hallmarking Centre (AHC). Any consumer can get jewellery tested at these centres for a fee, and they issue a proper assay report.

The methods they use:

• XRF (X-ray fluorescence) - non-destructive, fast, and accurate. The machine reads purity without harming the piece.
• Fire assay - the most precise method, used as the reference standard, though it consumes a small sample.

Both XRF and fire assay are mandated testing methods at BIS-recognised centres. A karat meter at a jeweller's counter is convenient, but an AHC report is the document that holds up for resale, loans, and disputes.

Why purity affects more than just price

Your gold's purity decides three things: what you pay now, what you get back when you resell, and how much a lender will offer against it.

Banks and jewellers evaluate purity before any buyback or gold loan, and they want certified, hallmarked gold with a visible purity mark and verifiable HUID. Non-hallmarked gold almost always fetches a lower offer, because the buyer has to absorb the uncertainty you didn't resolve.

There's also a legal safety net. Under BIS rules, if gold tests below its declared purity, the customer is entitled to compensation of twice the value of the shortfall, plus testing charges. That protection only exists because the piece was hallmarked in the first place.

Quick checklist before you buy

• Look for the BIS triangle logo, the purity number, and the HUID code.
• Open the BIS Care app and verify the HUID yourself.
• Confirm the karat matches what you're paying for (916 = 22K, 750 = 18K).
• Ask for an invoice that states net gold weight, purity, and hallmarking charges separately.
• For high-value pieces, get an AHC assay report.

Do those five things and purity stops being a leap of faith.

Read more: https://kamajewelry.com/blogs/insights/understanding-lab-grown-gold-science-authenticity-and-the-future-of-alchemy

FAQs

How do I check gold purity at home?

Read the hallmark first: look for the BIS logo, the three-digit purity number, and the six-character HUID code. Then verify the HUID free on the BIS Care app. Home tests like the magnet check can catch obvious fakes but can't confirm the exact karat.

What does 916 mean in gold?

916 is the fineness mark for 22K gold, meaning 91.6% pure gold. In the same system, 750 means 18K (75%) and 585 means 14K (58.5%).

Is the HUID code mandatory?

Yes. From 31 March 2023, gold jewellery sold in India must carry a six-character HUID code. You can verify it on the BIS Care app.

What's the difference between 22K, 18K, and 14K gold?

They're different purity levels. 22K is 91.6% gold and best for plain gold jewellery. 18K (75%) and 14K (58.5%) are harder and better suited to diamond and gemstone pieces that need durability.

Which gold is best to buy?

For plain gold jewellery and value retention, 22K is the usual choice in India. For diamond or stone-studded jewellery, 18K or 14K holds the stones more securely and resists daily wear.

Can the magnet test prove my gold is real?

No. It can flag obvious fakes since gold isn't magnetic, but passing it doesn't confirm purity. Use the hallmark and HUID verification instead.

At Kama, every piece carries its proper BIS certification, so the purity you pay for is the purity you get. Explore our gold collection ›

Sources: Bureau of Indian Standards (bis.gov.in) - hallmarking rules, HUID system, and consumer compensation provisions; BIS 2025 updates including 9K gold inclusion (effective 1 July 2025).