Polished Diamond
Polished Diamond
The finished, faceted diamond ready for grading, mounting, and sale
A polished diamond is a finished diamond that has been cut and polished from rough, ready for laboratory grading, mounting, or wholesale sale. The term distinguishes the midstream and downstream product of the diamond pipeline from rough diamonds, which are uncut crystals as recovered from the mine, and from bruted or pre-polished material, which has been shaped but not yet finished. Polished diamonds are the form in which most diamonds reach the consumer market.
How a polished diamond is graded
Polished diamonds are graded against the four Cs — carat weight, colour, clarity, and cut — by laboratories such as GIA, IGI, HRD, and AGS. A grading report describes each of these four attributes in standardised terms, and the report accompanying the stone has come to function as a near-currency document in the wholesale and retail trade. Polish grade and symmetry grade are reported separately as components of cut, alongside the overall proportions-based cut grade for round-brilliant diamonds.
Position in the pipeline
The diamond pipeline runs from rough mining at the upstream end through cutting and polishing at the midstream stage to retail jewellery sales at the downstream end. Polished diamonds are the midstream product, the form in which the industry transmits value from miners to retailers. Major polishing centres include Surat in Gujarat, Antwerp in Belgium, Ramat Gan in Israel, New York in the United States, and an emerging set of operations in Botswana and other producer countries seeking to capture beneficiation value.
Pricing and indices
Polished-diamond prices are tracked by published indices including the Rapaport Diamond Report, the IDEX Online price index, and the Polished Prices benchmark. These indices aggregate transaction data across size, colour, clarity, and shape categories to provide trade pricing transparency. The benchmark prices are reference points; actual transaction prices may run above or below the index depending on the specific characteristics of the stone, the relationship between buyer and seller, and current market conditions.
The polished trade
Polished diamonds change hands through a network of bourses, dealer-to-dealer transactions, online wholesale platforms, and direct sales from polishers to retailers. The principal bourses are the Diamond Dealers Club in New York, the Antwerp World Diamond Centre in Belgium, the Ramat Gan Diamond Bourse in Israel, the Bharat Diamond Bourse in Mumbai, and the Dubai Diamond Exchange. Membership of a recognised bourse, with its trade conduct rules and arbitration mechanisms, is the basis of trust on which much of the polished diamond trade depends.