A diamond price estimate with its working shown.
The short answer
What it does. It takes a specification for one loose round brilliant and estimates what that stone works out to in rand, including VAT, at three levels of the South African trade.
The number it gives you. It starts from one published cell of the Rapaport round list, a 1.00 to 1.49 carat G colour VS1 at 5,400 US dollars per carat on the list dated 20 March 2026, which converts at 16.50 rand to the dollar with 15 percent VAT to about R102,465 per carat. Dealer-direct is estimated at list less 20 percent, inside a band of less 10 to less 30 percent. A retail counter is estimated at roughly double the trade cost, which is the published keystone convention, and a branded showroom at roughly three times. For a 1.00 carat G VS1 that is about R82,000, about R164,000 and about R246,000.
What that number is not. It is not a quote, not a valuation, not an offer, and not a measurement of what South African sellers charge. It prices a loose stone, so a setting, the making and any certification fee sit on top. One cell of the list is benchmarked and everything else is an assumption, which the result panel names for your specification every time. Every figure moves when the list, the exchange rate or VAT moves, so redo the arithmetic rather than trusting the output, including this one.
Before you use the number
This site is written by one person, who works in the South African diamond trade. Read what follows as an argument from someone with a position in the industry rather than a neutral survey of it. The business that person is connected to is excluded from every dataset published on this site, and no business is named or recommended anywhere on it, including here. This tool describes how the levels of the trade differ. It does not tell you which one to buy from, and it does not link to a seller.
Configure the stone
Any change recalculates everything live.
Round brilliant only. Rapaport publishes fancy shapes on a separate list and that list is not on file here. An earlier version priced ten shapes off round-list arithmetic using factors that could not be sourced. They were removed rather than kept behind a caveat.
The same stone at three levels of the trade
What each level of the trade would work out to
Estimates on the method below, for a loose stone including VAT. Not quotes, and not observed prices. This is a description of how the trade is arranged, not a recommendation of which level to use.
What if you adjusted one grade
Measured at dealer-direct level. Tap any card to apply that swap. Every one of these deltas rests on an unbenchmarked colour, clarity or cut factor, so read the direction and the rough size rather than the exact rand.
Turn this into a real quote request
An estimate can tell you what to check. Only the actual stone, its grading report, its fluorescence, its make and an inspection can tell you what it is worth. Both buttons below are unaddressed on purpose: they carry your specification and the questions, and you choose who to send them to.
No confidence score is shown here. The previous version printed one, at 92 percent, with nothing behind it. What the tool can honestly tell you instead is which parts of your result come off the published list and which are assumptions, and that is stated in full above.
The method, in full, so you can redo it
Rapaport publishes a price list weekly that the trade quotes against. It is a grid of colour against clarity, within a weight bracket, by shape, in US dollars per carat. Rapaport states plainly that it is an asking price and that stones change hands at a discount to it, and that the discount moves with market liquidity. It is paywalled and trade-only, which is why most buyers cannot translate a quote back to its reference.
One cell of that list is on file here, and it is the only benchmarked number in this tool:
Rapaport round brilliant list, 20 March 2026. G colour, VS1 clarity, 1.00 to 1.49 carat bracket: 5,400 US dollars per carat.
$5,400 per carat x 16.50 USD to ZAR, live rate, 4 August 2026 x 1.15 15 percent VAT = R102,465 per carat, list equivalent, including VAT x 0.90 list less 10 percent = R92,200 for a 1.00 ct x 0.80 list less 20 percent = R82,000 for a 1.00 ct x 0.70 list less 30 percent = R71,700 for a 1.00 ct
Loose stone only. No setting, no making, no certification fee. Every figure includes VAT, on one basis throughout. Every figure moves when the list, the exchange rate or VAT moves, and the exchange rate moves everything proportionally: the same table at R18 to the dollar instead of R16.50 shifts a one carat by about nine percent.
Why 20 percent off list. A discount has to be assumed, because Rapaport says the list is an asking price and nobody publishes what South African dealers charge the public. Twenty percent is that assumption, taken as a plausible competitive dealer-direct level for a private buyer, and it is consistent with the trade conventions this site already sets out elsewhere. What I will not tell you is that it is corroborated by independent measurement, because it is not: nobody publishes the figure that would corroborate it, which is the whole reason a discount had to be assumed in the first place. There is one weak check available, and it is weak: the R82,000 this produces for a 1.00 carat G VS1 sits below the cheapest South African showroom listing in a July 2026 sample, which started at R105,000. That R105,000 was a finished ring with a setting in it, at a different specification, so the difference between the two numbers is not a saving and should not be read as one. The strength of this method is that you can reproduce it and substitute your own discount, not that the answer has been verified.
How the two retail lines are reached. Not from this site's own price data, which does not show a per-carat saving and is not used for this. They come from the published retail convention: keystone, where the counter price is roughly double the trade cost, and roughly three times at a branded showroom. Margins between one trade level and the next are thin, commonly 3 to 5 percent, so the dealer-direct level is used as a stand-in for the trade cost a retailer pays. That is a simplification and it is stated rather than hidden. The doubling happens at one point, when a stone leaves the trade for a retail floor, and it pays for rent, stock, staff, insurance and a brand.
What is assumed rather than benchmarked. Everything that moves away from that one cell. Every colour other than G, every clarity other than VS1, every weight bracket other than 1.00 to 1.49 carat, and the cut grade, which the list does not price at all. Those factors are relative assumptions and they are labelled as such in the result panel for whatever specification you have selected. Fancy shapes are not offered, because Rapaport publishes them on a separate list which is not on file here. An earlier version of this tool priced ten shapes and printed a confidence score of 92 percent. Neither could be sourced and both have been removed.
For the surrounding argument and the source material, see the Rapaport price list and jeweller discount guide, the wholesale diamond pricing explainer, the South African diamond price study, and the editorial policy, which sets out how this site is researched, what it will not do, and how to send a correction.
DiamondScope questions
What number does DiamondScope actually give me?
A rand estimate for one loose round brilliant diamond, including VAT, at three levels of the trade. It starts from one published cell of the Rapaport round list, a 1.00 to 1.49 carat G colour VS1, at 5,400 US dollars per carat on the list dated 20 March 2026. That converts at 16.50 rand to the dollar with 15 percent VAT to about 102,465 rand per carat. Dealer-direct is estimated at list less 20 percent, inside a band of less 10 to less 30 percent. A retail counter is estimated at roughly double the trade cost, which is the published keystone convention, and a branded showroom at roughly three times. For a 1.00 carat G VS1 that is about R82,000, about R164,000 and about R246,000.
What is that number not?
It is not a quote, not a valuation, not an offer, and not a measurement of what South African sellers charge. It prices a loose stone only, so a setting, the making and any certification fee sit on top of it. It is arithmetic on one published list cell plus assumptions that are stated on the page, and every figure moves when the list, the exchange rate or VAT moves.
Which parts of the calculation are benchmarked and which are assumed?
One cell is benchmarked: a round brilliant, 1.00 to 1.49 carat, G colour, VS1 clarity, from the list dated 20 March 2026. Everything that moves away from that cell is an assumption, because the list is paywalled and only that cell is on file here. That includes every other colour, every other clarity, every weight bracket outside 1.00 to 1.49 carat, and the cut grade, which the Rapaport list does not price at all. The tool names which of those a given result depends on, in the result panel, every time.
Why does the same specification cost so much more at a retail counter?
Because of where the margin sits, not because anyone is cheating. The published retail convention is keystone: the counter price is roughly double what the stone cost the counter, and a branded showroom runs to roughly three times. Margins between one trade level and the next are thin by comparison, commonly 3 to 5 percent. The doubling happens at the single point where a stone leaves the trade for a retail floor, and it pays for rent, stock, staff, insurance and a brand. Those are real costs for real services, and whether they are worth it to you depends on what you want from the purchase.
Why does it only price round brilliants?
Because Rapaport publishes fancy shapes on a separate list and that list is not on file here. An earlier version of this tool priced ten shapes off round-list arithmetic using per-shape factors that could not be sourced from anywhere. Those factors were removed rather than kept behind a caveat. If the fancy list is obtained the shapes come back, with the list date printed next to them.
What is Rapaport and why start from it?
Rapaport publishes a weekly price list that the diamond trade quotes against, structured as a grid of colour against clarity within a weight bracket, by shape, in US dollars per carat. Rapaport states plainly that it is an asking price and that stones change hands at a discount to it, and that the discount moves with market liquidity. It is paywalled and trade-only, which is why most buyers cannot translate a quote back to its reference. The trade convention is to buy at 10 to 40 percent below list, which is set out in full in the Rapaport price list and jeweller discount guide.
I have a GIA report number. Can DiamondScope verify it?
No. Paste the report number into gia.edu/report-check to confirm the report is real and that its grades match what you were told, then enter those grades here. Verifying the report is the more important of the two steps, and it is free.
Does DiamondScope recommend where to buy?
No. It describes three levels of the trade and what each one is, and it names no business anywhere. Which level suits you depends on your deadline, your budget, whether you want to try pieces on a hand, and whether you want a counter to go back to for resizing and valuations. The person who writes this site works in the South African diamond trade, so a recommendation from here on which tier to use would be worth very little, and none is offered.
Is it free, and does anything get stored?
Free, no signup, no paywall and no affiliate links. Nothing you enter is sent anywhere: the calculation runs in your browser and the only place your specification is written is the address bar, so you can copy the link.
Can I share or embed a result?
Yes. Copy share link puts your current specification in the URL, and anyone who opens it sees the same result recalculated on their device. There is also a paste-and-go embed snippet further down this page for putting the calculator on your own site, and the embedded version carries the same disclosure this page does.
What this specification means