Sell Polished Diamonds · Global
Sell polished diamonds to institutional buyers.
OnePiece connects sellers of GIA, HRD, and IGI certified polished diamonds with qualified institutional buyers and collectors in Dubai, Singapore, Hong Kong, New York, and Antwerp. Investment-grade single stones, commercial mixed lots, and exceptional gems.
The polished diamond market
The global polished diamond trade is concentrated in a small number of cities. Dubai, Singapore, and Hong Kong have emerged as the key Asian trading hubs — each with a distinct buyer profile. Dubai's DMCC attracts Gulf region collectors, Indian diaspora dealers, and global investment buyers seeking a tax-efficient trading environment. Singapore functions as the family office and wealth management gateway to Southeast and East Asian demand. Hong Kong connects mainland Chinese collectors to the international market.
New York and Antwerp remain dominant in the Western trade. New York's 47th Street district is the largest concentration of retail and wholesale diamond dealers globally. Antwerp, already the world's rough trading capital, also handles significant polished trade — particularly for European and Middle Eastern buyers.
Investment buyers — primarily family offices and HNW private collectors — concentrate their demand on D–F colour, VVS–VS clarity, round brilliant with GIA triple excellent. These buyers are price-conscious on the 4Cs and will not compromise on certification. Commercial buyers, by contrast, want mixed lots of G–J colour, SI clarity stones for manufacture or retail — they trade in volume and price per carat rather than individual stone quality.
Grading reports and why they matter
GIA — the Gemological Institute of America — is the globally recognised standard for polished diamond grading. A GIA grading report provides an independent, authoritative assessment of the 4Cs (colour, clarity, cut, carat weight) plus proportions, polish, symmetry, and fluorescence. It is the document institutional buyers rely on when pricing a stone without physical inspection.
HRD Antwerp and IGI are also accepted by our buyer network, though GIA commands the highest price premium because it is the most conservative and consistent grading lab. A stone graded by GIA as D/IF will trade at a premium to the same physical stone with an IGI report, because the market prices in the possibility of grade inflation from non-GIA labs.
A polished stone above 0.5 carats without a grading report from a recognised lab typically trades at a 15–30% discount to an equivalent certified stone. For any stone above 0.5ct, obtaining a GIA certificate before attempting a sale is almost always economically rational — the cost of certification (typically USD 100–300) is recovered many times over in better pricing. For stones below 0.5ct, melee lots are usually sold in mixed parcels without individual certs.
Investment-grade vs commercial polished
The distinction matters because the buyer pool, pricing mechanism, and settlement process differ significantly between the two categories.
Investment-grade polished: colour D–F (colourless), clarity VVS1–VS2 (eye-clean, high clarity), cut excellent or ideal, carat weight 1ct or above. Round brilliant is the most liquid shape — it has the broadest buyer pool and the most liquid secondary market. Investment buyers — family offices and private collectors — will pay full Rapaport or above for certified D/VVS1/EX stones in desirable sizes (1, 2, 3, 5, 10ct are the liquid sizes). These transactions are placed individually with qualified buyers and may take two to four weeks to complete at optimal pricing.
Commercial polished: G–J colour, SI clarity — the bread-and-butter of the global jewellery manufacturing industry. These stones are traded in parcel lots, priced per carat, and sold to manufacturers and retailers rather than end collectors. The buyer network here is volume-oriented; deals are faster but margin-thinner. If you have a mixed lot of commercial-grade stones, we can facilitate a parcel placement to a manufacturer buyer.
Stone specifications
Stone type
Polished — round brilliant, fancy shapes, investment parcels
Grading cert
GIA (preferred), HRD, or IGI — required for stones above 0.5ct
Colour range
D–Z; investment grade D–F; commercial G–J
Clarity range
FL–I2; investment grade VVS1–VS2; commercial SI1–SI2
Minimum carat
0.3ct for certified single stones; 10ct+ for mixed lots
Settlement
Bank escrow — funds held until stone delivery confirmed
Buyers
Dubai, Singapore, Hong Kong, New York, Antwerp
Treatments
None accepted — natural untreated stones only
GIA-certified stone or polished parcel to sell?
WhatsApp us with your stone details — cert number, carat weight, colour, clarity, and your price indication. We will advise on buyer options and realistic pricing within hours.
WhatsApp +60 19-873 8500