Selling a diamond back has rarely brought back the price
The word 'still' in the question assumes a diamond once held its value. The evidence says it mostly did not, and the gap is far older than lab-grown diamonds.
In 1982 the writer Edward Jay Epstein described what happened when ordinary owners tried to sell, in a cover story for The Atlantic titled 'Have You Ever Tried to Sell a Diamond?'. In one case, from 1974, a buyer in London paid £2,595 for a 1.4 carat stone from a reputable dealer, decided a week later to sell it, and got a best offer of £1,000. A New York diamond buyer told Epstein a half-carat ring that might cost $2,000 in a jewelry shop could be sold to his firm for only $600.
These are cases one reporter collected and estimates from people in the trade. They are not a survey, and they do not give the share of the price an owner would get back today.
None of this was a market crash. It was how the price of a diamond had been built all along.
Why a shop's price and a buyer's offer are two different prices
A shop buys its stones at wholesale and adds its own margin. Epstein reported that the markup on a diamond and its setting could run from 100 to 200 percent, depending on the store.
When you sell, you are on the other side of that margin. The New York buyer Epstein interviewed said his firm could usually pay at most 90 percent of the current wholesale price, and often less, because the setting is sold as scrap and the buyer leaves room for error. Shops, Epstein wrote, generally preferred not to buy back stones at all, because the honest offer would look insulting next to the receipt.
So the receipt records the retail price. An offer to buy it back is made at wholesale or below. Those were never going to match.
One company decided how many diamonds reached the market
Diamonds start as rough stones dug from mines and are cut and polished before they reach a shop. For most of the 20th century, most of that rough supply passed through one company, De Beers. According to the Gemological Institute of America, by 1900 De Beers controlled an estimated 90 percent of the world's rough diamond production.
Holding most of the supply meant De Beers could decide how much reached the market, and so keep prices steady. Epstein described how, when the Soviet Union began mining diamonds, De Beers offered it a 'single channel' for selling them rather than compete on price.
That role has largely gone. The Gemological Institute of America says De Beers 'greatly reduced its role as the custodian of diamond supply', and that diamonds now reach the market through many channels instead of one.
'A diamond is forever', read as 'never sell'
Controlling supply was half the job. The other half was making sure the stones already sold never came back onto the market and competed with new ones.
In 1938 De Beers hired N. W. Ayer, an American advertising agency. A 1947 strategy plan from the agency, quoted by Epstein, set out to make the engagement ring 'a psychological necessity'. De Beers credits Frances Gerety, a copywriter at the agency, with writing the line 'A Diamond Is Forever' in 1947. It first ran in advertisements in 1948.
Epstein's reading of the line is blunt. The idea, he wrote, was that diamonds were forever 'in the sense that they should never be resold'. That is his interpretation of the campaign, not something its writer is recorded as saying. On his reading, a stone kept in a drawer for life cannot drag down the price of the next one.
In the US, a lab-grown diamond is a diamond, with a label
Diamonds can now be grown in factories, with the same carbon crystal as a mined stone. In July 2018 the US Federal Trade Commission revised its Jewelry Guides, its guidance for sellers. The new definition of a diamond no longer contains the word 'natural', so a grown stone fits it.
There is a condition. The Guides call it unfair or deceptive to use a gem's name for a grown stone unless the name comes right after a word such as 'laboratory-grown' or 'laboratory-created', printed just as clearly.
There is also a limit. The Guides say they 'do not operate to bind the FTC or the public'. They are the agency's view of what would mislead a buyer, not a law of their own, though a claim that goes against them can still lead the agency to bring a case under the law it enforces.
Once anyone could grow a diamond, its price kept falling
De Beers tried selling grown diamonds itself. Its brand Lightbox launched in 2018 at a flat retail price of $800 per carat, a carat being the unit diamonds are weighed in.
On 8 May 2025 De Beers said it would close Lightbox. It said wholesale prices for lab-grown jewelry diamonds had fallen 90 percent since Lightbox launched. That is a fall in wholesale prices, not a fall from the $800 Lightbox charged shoppers. Its chief executive, Al Cook, told the trade magazine JCK that lab-grown stones could now be bought 'in supermarkets for $200'.
The analyst Edahn Golan, who has tracked lab-grown wholesale prices since July 2018, put his index 96 percent below its starting point in his Q2 2026 price list, published on 7 July 2026, with prices down 13 percent from a year earlier. His figures also show the fall slowing, with one-carat round stones up 1 percent on the year. A stone that can be made in growing numbers has lost the scarcity that once held diamond prices up.
Natural diamond prices : the indexes do not agree
For mined diamonds there is no single price, and the people who measure it report different things.
De Beers' own figures, published on 30 July 2026, show its average rough diamond price index 16 percent lower in the first half of 2026 than a year earlier, and the average price it got for each carat down from $155 to $105. De Beers said part of that larger fall came from a change in the mix of stones it sold.
Rapaport, a trade price service that tracks polished stones, said on 4 February 2026 that 'diamond demand is permanently lower because of synthetics, China's slowdown, and social changes like dropping marriage rates'. By 6 October 2026 it was reporting a second monthly rise for one-carat stones, of 0.3 percent in September, and its index for 0.30 carat stones up 15.1 percent since the start of the year. Its index tracks the asking prices of selected polished stones, not completed sales, shop prices or what an owner is offered.
These numbers measure different things : rough stones or polished ones, small sizes or large, a half-year average or one month. Read together, they say natural prices fell hard and some have begun to steady. They do not give one number for what a diamond is worth now, and none of them tells an owner what their own ring would fetch.
The company that held the system together is for sale
In May 2001 De Beers' shareholders approved an $18.7 billion buyout by a group including the mining company Anglo American and the Oppenheimer family, JCK reported at the time ; the first offer had been $17.6 billion. Anglo American later came to own 85 percent of De Beers.
Anglo American has since written down what De Beers is worth on its books three times. After the latest cut, announced in February 2026, Anglo values the whole De Beers business on its books at $2.3 billion, against $9.2 billion in 2023; Anglo's own share of that is $1.9 billion. De Beers' revenue fell to $1.6 billion in the first half of 2026, from $2.0 billion a year earlier.
Anglo American has picked a preferred bidder : the Global Diamond Consortium, led by Gareth Penny, a former De Beers chief executive. On 29 July 2026 Bloomberg reported a price of about $1 billion for Anglo's 85 percent stake, roughly $750 million up front and $250 million later, and said the terms were not final. A day later Anglo's chief executive, Duncan Wanblad, said the company was in the final rounds of negotiation and hoped to sign by the end of the year. On 7 October 2026 he said negotiations were still under way.
The government of Botswana, which owns the other 15 percent of De Beers and produces more than 70 percent of its diamonds, has to approve the sale. Its minister said the sale would likely be concluded by the final quarter of 2026, subject to conditions. As of 8 October 2026 we found no announcement from Anglo American that a deal had been signed.
- Shareholders OK De Beers buyout (JCK)
- Anglo American, De Beers 1Q 2026 (JCK)
- Anglo American 2025 annual results script
- Interim financial results for 2026 (De Beers Group)
- Anglo American mulling $1B De Beers sale (Rapaport)
- Anglo picks Gareth Penny-led consortium as top De Beers bidder (Rapaport)
- Ex-De Beers chief leads bid for diamond giant (Mining.com)
- De Beers second half 2026 (JCK)
What the receipt was really paying for
A diamond's price in a shop was never a promise of what someone would pay for it later. Two separate things explain why. The first is the gap between buying and selling : the shop's margin, and a buyer who has to resell the stone and leaves room for error. That gap would exist even without De Beers. The second is the price level itself, which De Beers held up for decades by limiting supply and by advertising that, in Epstein's reading, taught buyers never to sell.
Lab-grown stones and the sale of De Beers bear on the second. Grown stones have weakened the idea that diamonds are scarce, and the company that ran the system is being sold. Neither changes the first. The old examples show how wide the gap could be, but no one has a single current figure for how wide it is today. The stone in the drawer has not changed. The receipt recorded what it cost to buy it, and that was never the price of selling it again.
