What the Purity Numbers Mean
Gold purity is expressed as a fineness — the number of parts pure gold per 1,000 parts of total metal. The three most common fineness marks on Indian jewellery are:
- 999 — 24-karat, essentially pure gold. Used for coins, bars, and investment gold.
- 916 — 22-karat gold, containing 91.6% pure gold. The most common standard for Indian jewellery, including the traditional bridal gold popular in Madurai.
- 750 — 18-karat gold, containing 75% pure gold. Common in modern and diamond-set jewellery.
- 585 — 14-karat gold, containing 58.5% pure gold. Less common in India; seen in imported jewellery and some lightweight pieces.
The remaining metal in each alloy is typically silver, copper, or zinc — added to increase hardness and durability.
How Hallmarks Appear on Your Jewellery
Under the BIS (Bureau of Indian Standards) hallmarking system, the fineness mark is stamped directly on the jewellery — typically on the inner surface of a bangle, the clasp of a necklace, or the shank of a ring. Since 2021, the BIS system has also included a unique six-digit HUID (Hallmark Unique Identification) number that allows each piece to be traced back to the assaying centre that tested it.
On older jewellery — including much of the traditional jewellery common in Madurai — you may see just the karat mark (22K, 18K) or the BIS hallmark symbol without the HUID code. These are still valid purity indicators, but they cannot be verified digitally the way HUID codes can.
Karat-to-fineness conversion: 24K = 999, 22K = 916, 18K = 750, 14K = 585, 9K = 375. When comparing offers, always ensure the buyer is using the correct fineness for your specific piece. A 916 piece priced at 750 rates would cost you roughly 18% of its value.
How Purity Directly Affects Your Resale Price in Madurai
Purity is the most important single variable in calculating a gold sale price. Starting from the same base IBJA rate, a gram of 916 gold is worth 22% more than a gram of 750 gold. For a 20-gram lot at an IBJA rate of ₹7,200 per gram:
- 916 purity: ₹7,200 × 0.916 × 20 = ₹1,31,904
- 750 purity: ₹7,200 × 0.750 × 20 = ₹1,08,000
- 585 purity: ₹7,200 × 0.585 × 20 = ₹84,240
This is why verifying your jewellery's actual purity through XRF testing — rather than accepting a buyer's verbal assessment — can make a significant financial difference on any sizeable lot.
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