This page exists because the honest answer is unwelcome and most of the sites that rank for the question are selling lab-grown diamonds. The answer is: almost none. Here is why, with sources, and then the more useful question, which is how to buy so that it does not matter.

There is no secondary market to speak of

Three things make a secondary market: buyers, a reference price, and scarcity. Lab-grown diamonds have none of them.

Buyers. As early as 2019 JCK found that the major US consumer-to-business diamond buyers would not purchase lab-grown at all, and that national chains excluded lab-grown from their trade-in programmes; the "market" consisted of a handful of lab-grown retailers offering upgrade credits against a larger future purchase 1. JCK's 2025 follow-up found the picture little changed: a nascent trade-in practice among some lab-grown sellers, and most retailers still declining buybacks because they could not predict what the stones would be worth 2. UK practice is the same. Pawnbrokers and diamond buyers price the metal and, if they accept the stone at all, price it at wholesale replacement cost, which is the next point.

Reference price. Mined diamonds trade against the Rapaport list, which gives buyer, seller and valuer a shared number to discount from. Lab-grown has no equivalent, so resale offers are inconsistent and tend to anchor on the lowest wholesale price the buyer can find 6.

Scarcity. Supply is unlimited. JCK, citing Paul Zimnisky, puts the fall in wholesale lab-grown prices at about 96 per cent since 2018, with a further 26 per cent drop in 2025 and 13 to 14 per cent year on year in the first half of 2026 3. A buyer can always source a new stone for less than they would pay you for yours.

What that looks like in pounds

UK insurers have done the sums. NFU Mutual told Insurance Times in March 2024 that a three-carat lab-grown diamond valued at £16,500 in 2021 was worth £7,500 by 2023, while a comparable natural stone had gone from £55,000 to £70,000 4. The same insurer had warned in 2023 that lab-grown stones "will likely decrease in relative value" because they are not scarce 5. Retailer blogs that attempt a figure put typical resale at 20 to 40 per cent of the original price through consignment, and less for a quick sale 6; those are US figures from interested parties and should be read as the optimistic end.

GIA's decision in 2025 to stop grading lab-grown diamonds on colour and clarity, on the grounds that most fall into a very narrow quality range, removes another prop: without fine grades there is less to differentiate one second-hand lab-grown stone from another 7.

Why this is not an argument against buying one

Nobody buys a sofa, a suit or a car expecting to sell it for what they paid. Jewellery is the one consumer purchase where people have been told otherwise, and mostly by people selling diamonds. In practice a mined diamond bought at retail also sells back at a heavy discount; the difference is that it has a floor and a lab-grown stone does not yet.

So the buying logic for lab-grown is different, and simpler:

  1. Spend on the jewellery, not the stone. The stone is now a small part of a well-made ring's cost. Design, metal, setting and the maker's time hold their worth as a piece you wear; the loose stone does not. The price page shows how little of a 2026 ring price is stone.
  2. Do not pay a premium for "value retention". Any retailer who implies a lab-grown diamond is an asset is contradicting every market source on this page. Walk.
  3. Read trade-in offers as marketing. A credit worth part of the original price, spendable only on a purchase of one and a half or two times that price with the same retailer 1, is a retention scheme.
  4. Insure for replacement, and revalue. Because replacement cost falls, an insurance valuation from 2022 overstates what you need to insure. The insurance page covers this.
  5. Enjoy the upside. The same collapse that destroys resale value is what lets you wear two carats of D-colour diamond for the price of a modest mined half-carat. That is the trade.

The short version

If you want a diamond that can be sold later, buy a mined one and accept a heavy loss. If you want a diamond to wear, a lab-grown stone in a ring you love is the better purchase in 2026, provided you go in knowing the stone's resale value is close to nil. This record would rather say that plainly than let you find out at a pawnbroker's counter.