Complete Guide to Gold Purity: 22K vs 24K vs 18K Gold Explained
Gold purity is measured in karats (K), with 24K being the purest form at 99.9%. In Indian jewellery, 22K gold (91.6% pure) is the standard because it balances high purity with the durability needed for wearable ornaments. The Bureau of Indian Standards (BIS) certifies gold purity through its hallmarking scheme, and every piece at Sri Amman Jewellery carries this official certification.
Published by Sri Amman Jewellery, Salem • Expert jewellers since 1998
What is Gold Purity?
Gold purity refers to the proportion of pure gold in an alloy. Pure gold (24K) is extremely soft, so it is mixed with metals like copper, silver, and zinc to create alloys suitable for jewellery. The karat system divides gold into 24 parts, where 24K equals pure gold and lower karats indicate a proportionally lower gold content.
For example, 22K gold contains 22 parts gold and 2 parts alloy metals. Mathematically: (22/24) × 100 = 91.67% pure gold. This is why the BIS marks 22K gold as “916” — representing 91.6% purity.
Gold Karat Comparison Chart
| Karat | Gold % | BIS Code | Colour | Best For |
|---|---|---|---|---|
| 24K | 99.9% | 999 | Bright yellow | Investment (coins, bars) |
| 22K | 91.6% | 916 | Rich yellow | Indian jewellery (standard) |
| 18K | 75.0% | 750 | Warm yellow | Diamond-set, western designs |
| 14K | 58.3% | 585 | Lighter yellow | Budget-friendly daily wear |
22K vs 24K Gold: Which Should You Buy?
22K Gold (916)
- • 91.6% pure gold
- • Durable enough for daily wear
- • Standard for Indian jewellery
- • Rich yellow colour
- • BIS Hallmarked as 916
- • Best for: necklaces, bangles, rings, earrings
24K Gold (999)
- • 99.9% pure gold
- • Too soft for jewellery
- • Highest investment value
- • Brightest yellow
- • BIS Hallmarked as 999
- • Best for: coins, bars, investment
How to Check Gold Purity
- 1
Locate the hallmark stamp
Check the inner surface of the jewellery — inside of rings, clasp areas, or inner side of bangles.
- 2
Identify the BIS logo
The triangular BIS logo confirms the piece was tested at an authorized assaying centre.
- 3
Read the purity number
999 = 24K, 916 = 22K, 750 = 18K, 585 = 14K.
- 4
Note the HUID
Record the 6-digit alphanumeric Hallmark Unique ID number.
- 5
Verify online
Visit bis.gov.in or use the BIS Care app to verify your HUID.
Frequently Asked Questions
What does 22K gold mean?▼
22K gold means 22 out of 24 parts are pure gold, equalling 91.6% purity. The remaining 8.4% consists of alloy metals like copper and silver that add strength and durability for jewellery making.
Is 24K gold good for jewellery?▼
24K gold (99.9% pure) is too soft for everyday jewellery. It bends and scratches easily. That is why 22K gold (91.6% pure) is the preferred standard for Indian jewellery — it provides excellent purity with adequate durability.
What is 916 gold?▼
916 gold refers to 22-karat gold. The number 916 indicates that the gold contains 91.6% pure gold. This is the BIS hallmark designation for 22K gold in India.
Which is better for investment: 22K or 24K gold?▼
For investment in coins or bars, 24K gold is preferred due to higher purity. For jewellery that you wear, 22K gold is better because it retains high gold content while being durable enough for daily use.
How can I check the purity of my gold jewellery?▼
Look for the BIS hallmark on your jewellery. It should have a BIS logo, purity number (916 for 22K), and a 6-digit HUID number. You can verify the HUID online at bis.gov.in or through the BIS Care app.
Buy BIS Hallmarked Gold Jewellery
Every piece at Sri Amman Jewellery is 100% BIS Hallmarked with transparent pricing.