How to Check Gold Purity: A Complete Guide for Smart Buyers
By Anika Iyer · 25 June 2026
Gold is more than just a precious metal—it is a symbol of wealth, tradition, and financial security. Whether you're purchasing jewellery for a wedding, investing in gold coins, or planning for the future, verifying the purity of gold is essential.
This guide explains the different ways to check gold purity, understand hallmark markings, and avoid common mistakes while buying gold.
Quick Summary
- Always look for a BIS Hallmark and HUID.
- Understand what karat numbers (24K, 22K, 18K, etc.) mean.
- Home tests can indicate authenticity but cannot accurately measure purity.
- For complete accuracy, use professional testing methods such as XRF or electronic gold testers.
- Purchase gold only from trusted jewellers and keep the invoice for future resale.
What Does Gold Purity Mean?
Gold purity indicates how much pure gold is present in a jewellery item or coin.
Since pure gold is naturally soft, it is mixed with other metals like silver, copper, nickel, or zinc to improve strength and durability.
The higher the karat, the higher the percentage of pure gold.
| Karat | Gold Purity | Fineness Mark |
|---|---|---|
| 24K | 99.9% | 999 |
| 23K | 95.8% | 958 |
| 22K | 91.6% | 916 |
| 20K | 83.3% | 833 |
| 18K | 75.0% | 750 |
| 14K | 58.5% | 585 |
| 10K | 41.7% | 417 |
How to Check Gold Purity
There are several methods to verify whether your gold is genuine and determine its purity.
1. Check the BIS Hallmark
The easiest and most reliable method is inspecting the jewellery for a BIS Hallmark.
A genuine hallmarked gold ornament typically contains:
- BIS logo
- Purity mark (916, 750, 585, etc.)
- Hallmark Unique Identification (HUID)
- Jeweller's identification mark
The hallmark certifies that the jewellery has been tested according to Indian standards.
2. Verify the HUID Online
Every hallmarked jewellery piece now carries a unique HUID number.
You can verify it through:
- BIS CARE Mobile App
- BIS Hallmark Portal
After entering the HUID, you'll see:
- Gold purity
- Jeweller details
- Hallmarking centre
- Hallmark date
- Jewellery type
This helps confirm that the hallmark is genuine and not counterfeit.
3. Magnet Test
Gold is not magnetic.
If your jewellery strongly sticks to a magnet, it likely contains a significant amount of other metals.
Keep in mind: Passing this test doesn't guarantee pure gold because several non-gold metals are also non-magnetic.
4. Vinegar Test
Apply a few drops of white vinegar.
- Genuine gold usually remains unchanged.
- Fake gold may discolor or react.
This is only a preliminary authenticity test and should not replace professional verification.
5. Water (Float) Test
Drop the item into a container filled with water.
- Real gold is dense and sinks quickly.
- Lightweight fake jewellery may float.
Again, this only helps identify obvious counterfeits.
6. Observe Colour and Weight
Pure gold has:
- Rich yellow colour
- High density
- Noticeable weight compared to similarly sized fake jewellery
However, appearance alone should never be considered proof of purity.
Professional Gold Purity Testing
When accuracy matters—especially for resale, loans, or investments—professional testing is recommended.
Electronic Gold Tester
Jewellers use electronic karat meters to quickly estimate gold purity without damaging the jewellery.
Advantages
- Fast results
- Non-destructive
- Good accuracy
X-Ray Fluorescence (XRF)
One of the most accurate methods available.
Benefits include:
- No damage to jewellery
- Measures complete metal composition
- Highly accurate purity analysis
Nitric Acid Test
Professionals apply nitric acid to observe chemical reactions.
Although highly accurate, this method can slightly affect the surface and should only be performed by trained experts.
Density Testing
Since pure gold has a unique density, professionals compare weight and volume to estimate purity.
This is commonly used for coins and bullion.
Understanding Hallmark Numbers
Hallmark numbers represent the percentage of pure gold in the jewellery.
| Hallmark | Meaning |
|---|---|
| 999 | 24K Gold |
| 958 | 23K Gold |
| 916 | 22K Gold |
| 750 | 18K Gold |
| 585 | 14K Gold |
| 417 | 10K Gold |
These numbers are internationally recognized indicators of gold purity.
Why Gold Purity Matters
Checking purity isn't just about authenticity.
Higher purity affects:
- Investment value
- Resale price
- Gold loan eligibility
- Insurance valuation
- Long-term wealth preservation
For jewellery, the ideal purity depends on its purpose.
- 24K: Investment bars and coins
- 22K: Traditional jewellery
- 18K: Diamond and gemstone jewellery
- 14K: Daily wear jewellery
Tips Before Buying Gold
Follow these best practices:
- Buy only from trusted jewellers.
- Always ask for a tax invoice.
- Verify the BIS Hallmark and HUID.
- Compare current gold prices before purchasing.
- Avoid buying jewellery without purity certification.
- Preserve invoices and certificates for resale or insurance.
Common Mistakes Buyers Make
Many buyers unknowingly make these mistakes:
- Trusting appearance alone
- Ignoring hallmark verification
- Buying solely because of discounts
- Forgetting to verify HUID
- Assuming every yellow metal is real gold
- Not checking making charges separately
Frequently Asked Questions (FAQ)
How can I check gold purity at home?
You can inspect the hallmark, perform a magnet test, vinegar test, or water test. These methods provide only basic indications. Professional testing is required for accurate purity measurement.
What does 916 mean on gold?
A 916 hallmark means the jewellery contains 91.6% pure gold, which is equivalent to 22 Karat gold.
Is 24K better than 22K?
24K is purer but softer. For jewellery, 22K is generally preferred because it is more durable while still containing a high percentage of gold.
Can fake gold have a hallmark?
Counterfeit hallmarks do exist. Always verify the HUID using the BIS CARE app or official BIS website before purchasing.
Which gold is best for daily wear?
14K and 18K gold are more durable and better suited for everyday jewellery.
Which gold is best for investment?
24K gold bars and coins are generally preferred for investment because they contain the highest gold purity.
Does the magnet test always work?
No. Real gold is non-magnetic, but many fake metals are also non-magnetic. The magnet test should only be used as an initial check.
Why is hallmark verification important?
Hallmark verification confirms that the jewellery meets certified purity standards and protects buyers from fraud.
Bottom Line
Buying gold is a significant financial decision, and verifying its purity should always be your first step. While simple home tests can help identify obvious fakes, they cannot accurately determine gold content. Always look for the BIS Hallmark and HUID, verify them through official channels, and rely on professional testing whenever precision is important.
Following these steps helps ensure that your gold retains its value, qualifies for better resale or loan offers, and remains a secure long-term investment.
This article is for general information only and isn't financial, investment, or tax advice. Please consult a qualified financial advisor before making investment decisions — see today's gold and silver rates to track current prices.