Receiving the jewellery was usually not taxed
Jewellery is treated as property for the gift rules, but the common family situations are exempt. A gift received on the occasion of your marriage is exempt on receipt with no monetary limit, and the occasion is read around the wedding, not only the ceremony day, so wedding jewellery and streedhan are not taxed when received (Section 56(2)(x)). A gift from a relative, the defined list covering parents, siblings, grandparents and their spouses, is likewise exempt whatever it is worth.
The only case that is taxed on receipt is jewellery from a non-relative, outside the marriage occasion, where the total value in the year crosses ₹50,000, and then the whole amount is taxed as income from other sources. So a colleague gifting you an expensive piece for no occasion could be caught, but the wedding and family gifts that make up most people's jewellery are not.
What the jewellery is treated as costing on sale
Because you never paid for gifted jewellery, the natural question is what your cost is. The law carries the giver's cost across to you (Section 49(1)): what the person who gifted it to you originally paid for it becomes your cost. For pieces bought before 1 April 2001, you can use their value on that date instead.
Just as important, the giver's holding period counts as part of yours (Section 2(42A)), so a necklace a grandmother held for decades is long-term in your hands from her time, not from the day of your wedding. And in the rare case where the receipt was taxed, a non-relative gift over the threshold, the value that was taxed then becomes your cost instead (Section 49(4)), so the same value is never taxed twice.
The gain, and the TDS reality
On sale, jewellery held more than twenty-four months produces a long-term gain, taxed for an NRI at the flat 12.5% with no indexation for sales on or after 23 July 2024 (Section 112). Because the cost carries from the giver, often at a much older and lower price, the gain can look large on paper, but the long-term rate and, for old pieces, the 2001 value keep the actual tax modest.
On TDS, jewellery is not immovable property, so the 1% property rule does not apply and there is no dedicated buyer-deduction on a jeweller's purchase. Strictly, a buyer paying a non-resident a sum that contains a taxable gain should deduct under Section 195, but in practice bullion dealers rarely do on an over-the-counter sale. Either way, the gain is yours to report, and a practising CA computes it with the carried-over cost so you pay the right amount and no more.