GIA Certified Natural Diamonds · Bedfordview, Johannesburg
GIA certified natural diamonds, polished in-house to GIA Excellent cut.
Every loose diamond Prodiam sells is a natural stone with an independent laboratory report, GIA, with EGL accepted on selected pieces, and every round brilliant is polished to GIA Excellent cut grade on our own bench at Procut DCW in Bedfordview. The report travels with the stone, the cut grade is the top of GIA’s scale, and you can verify any certificate yourself before you settle. Priced on application against the wholesale list, with insured delivery anywhere in South Africa.
Enquire about a certified stone See loose diamonds → How to read a GIA report →
GIA certified, cut and set on the Prodiam bench
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2.25 ct round brilliant, GIA Excellent cut -
0.61 ct I VS1 solitaire, GIA certified -
18k gold classic solitaire, certified stone
Past pieces, photographed at the bench. Stones are sold and set to order and priced on application; nothing shown is offered as stock.
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Only natural diamonds
Mined-Earth, never lab-grown. Kimberley Process documented from the mine of origin.
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GIA & EGL certified
Every loose stone certified by the GIA or EGL. Cert PDF supplied per stone.
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Insured overnight delivery
Brink’s, G4S or our nominated jewellery courier across South Africa. Ferrari Group / FedEx Custom Critical international.
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14-day in-person exchange
In-person sales at the viewing room come with a 14-day exchange courtesy on stock pieces. Distance-sale CPA cooling-off applies.
What a GIA certificate actually tells you
A GIA report is an independent grading of a single diamond by the Gemological Institute of America, the laboratory whose grading is the international benchmark. It records the stone’s carat weight, colour, clarity and, for round brilliants, cut, along with its precise measurements and a unique report number. Because GIA never buys or sells diamonds, the report is a neutral description: it is the document that lets you compare two stones on the same terms instead of on a salesperson’s word. The full briefing on the 4Cs of diamond grading explains how the four grades interact.
Why we cut to GIA Excellent
Of the 4Cs, cut is the one a cutting house controls, and it is the one that decides how alive a diamond looks. GIA grades cut on a scale that tops out at Excellent, awarded when a round brilliant’s proportions, polish and symmetry fall in the range that returns the most light. We polish our round brilliants to GIA Excellent cut grade on our own bench at Procut DCW, that is the point of the single-custody chain, where we cut the rough rather than buying stones in already polished to someone else’s standard. A well-cut Excellent stone can also carry a slightly lower colour grade and still face up white, which is often the smartest place to spend a budget.
GIA and EGL, what we certify with, and what ships with your stone
GIA is our primary laboratory and the one most clients ask for. We also accept EGL certificates on selected stones; the two laboratories grade to their own standards, so we are always clear about which report a stone carries and quote like grade for like grade. Whichever it is, the report travels with the stone, and every finished piece is supplied with a written insurance valuation in addition to the diamond’s report.
| On the report | What we supply |
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| Carat | 0.30 ct to 10 ct and above |
| Colour | D to K (and fancy colours on request) |
| Clarity | IF to SI2 |
| Cut | Round brilliants polished to GIA Excellent cut grade |
| Laboratory | GIA primarily; EGL accepted on selected stones |
| With every stone | Its report; finished pieces add a written insurance valuation |
How to verify a GIA report yourself
You do not have to take anyone’s word for a grade. Every GIA report has a unique number; enter it into GIA’s free Report Check service on gia.edu and the original grading appears, which you match against the stone and the report in your hand, carat, colour, clarity, cut and measurements should all agree. Larger stones are laser-inscribed with the report number on the girdle, readable under magnification. We encourage every client to verify before settling; the step-by-step is in how to read a GIA report.
From certified stone to finished piece
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Brief
Carat, colour and clarity range, shape, budget and any deadline. We respond within 24 hours.
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Candidate stones
We pull certified stones to your brief, each with its GIA or EGL report for you to read and verify.
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Verify & choose
Check the report number against GIA Report Check, compare the stones on the daylight tray or by video, and choose.
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Take it loose or set it
Keep the certified stone as it is, or have it set into a made-to-order piece at the bench.
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Hand-over
Collection at Bedfordview or insured overnight courier nationwide. The report, and a written valuation for finished pieces, included.
Ready to choose a stone? See the loose diamonds currently on the bench, ask us to source a specific certified stone, or read how we buy and cut as a diamond dealer and cutting house in South Africa.
GIA certified diamonds: common questions
Are Prodiam’s diamonds GIA certified?
Yes. Prodiam works in natural diamonds only, and stones are certified by the Gemological Institute of America (GIA), with EGL (European Gemological Laboratory) accepted on selected pieces. Every loose diamond ships with its independent laboratory report, and round brilliants are polished to GIA Excellent cut grade on our own bench at Procut DCW. You receive the report and a written insurance valuation with the stone.
What is GIA Excellent cut grade?
Cut is the C that governs how much light a diamond returns, its brilliance and fire, and GIA grades it on a scale that tops out at Excellent. Excellent means the proportions, polish and symmetry are within the range that returns the most light. GIA only assigns a cut grade to round brilliants; for fancy shapes it grades polish and symmetry instead, which is why a skilled cutter matters most on ovals, emeralds and the like. We polish our round brilliants to GIA Excellent on our own bench.
Do you sell EGL certified diamonds as well as GIA?
GIA is our primary laboratory and the one most buyers ask for, because its grading is the international benchmark. We also accept EGL certificates on selected stones. The two laboratories grade to their own standards, so we are clear about which report a stone carries before you commit, and we quote like grade for like grade so you can compare fairly. The report always travels with the stone.
How do I verify a GIA certificate myself?
Every GIA report carries a unique report number. Enter it into GIA’s free Report Check service on gia.edu and the original grading appears, carat weight, colour, clarity, cut and measurements, so you can match it against the stone and the report in your hand. Larger stones are also laser-inscribed with the report number on the girdle, readable under magnification. We encourage you to verify before you settle; a stone that cannot be verified is not a stone you should buy.
Does every diamond come with its certificate and a valuation?
Yes. Every loose diamond is supplied with its GIA or EGL laboratory report, and every finished piece is supplied with a written valuation for insurance in addition to the stone’s report. If you are buying remotely, the report details are shared before purchase and the physical report travels with the insured delivery.