What the numbers mean
The three-digit mark is parts of gold per thousand parts of metal. 999 is 99.9% pure gold — 24 karat. 916 is 91.6% pure — 22 karat, the balance being alloy metals such as copper, silver or zinc. 750 is 18 karat, 75% pure.
Karat is the older fractional notation: 24 karat is pure, so 22/24 equals 91.6% and 18/24 equals 75%. Both systems describe the same thing.
Why jewellery is 916 and not 999
Pure gold is soft. A 999 bangle would deform in ordinary wear and could not hold a stone setting or a clasp. Alloying to 916 gives enough hardness for daily-wear ornaments while keeping the piece unmistakably gold in colour and value.
999 is therefore reserved for coins, minted bars and investment products, where the metal is not being worked into a wearable form.
How the two rates relate
The 916 rate should be exactly 91.6% of the 999 rate for the same weight. If the 999 rate is ₹10,000 per gram, the 916 rate is ₹9,160. Anything meaningfully higher is undeclared margin.
This also tells you what to expect on resale: a 916 piece returns 91.6% of the fine-gold value of its weight, less any refining deduction — never the making charges you paid.
What the BIS hallmark certifies
A BIS hallmark on Indian jewellery carries the BIS mark, the purity grade, and a six-digit alphanumeric HUID unique to that article. The mark certifies purity only — it says nothing about design value, stone quality or the fairness of the making charge.
The HUID can be checked in the BIS CARE app. Do that before payment, not after: it confirms the article was registered by a licensed jeweller and assayed at a recognised centre.
Common misunderstandings
916 is not a brand and is not exclusive to any region or chain. 'KDM' is an obsolete cadmium-soldered designation and should no longer be sold. And a hallmark does not make a price fair — it makes the purity verifiable.