Why Are Diamonds So Expensive? Pricing, Rarity, and Resale
Why are diamonds so expensive? Three things mostly: the cost of getting them out of the ground, a quality grading system called the 4Cs that prices each stone, and one of the most successful marketing campaigns in history that taught the world a diamond was the only acceptable engagement stone. At Vanhess Jewellery in Coquitlam, BC, customers ask us this almost weekly, and the honest answer mixes real scarcity with manufactured demand. Diamonds cost what they cost partly because they are hard to mine and partly because we were all told for eighty years that they should.
The 4Cs set the price of any given stone
Two diamonds of the same weight can differ wildly in price, and the reason is the 4Cs: carat, cut, colour, and clarity. Carat is weight. Cut is how well the stone was shaped to return light. Colour grades how close to colourless it is. Clarity grades how free it is of internal flaws. The GIA, which created the 4Cs in the mid-twentieth century, treats these as the universal language for grading and pricing diamonds.
Cut is the one we tell customers to prioritise, because GIA rates it as the biggest driver of how much a diamond sparkles. A large stone with poor cut looks dull. A smaller, well-cut stone outshines it. You are paying for all four, but cut is where your money does the most visible work.
Mining cost and natural scarcity
Gem-quality diamonds are genuinely uncommon. Most diamonds pulled from the earth are industrial grade, and only a small fraction are good enough for jewellery. Mining them is expensive: companies move enormous volumes of rock to recover a small amount of gem-quality material, then sort, cut, and polish it through many hands before it reaches a store. That supply chain adds real cost at every step.
So part of the price is honest scarcity and honest labour. But scarcity alone does not explain why a diamond, specifically, became the default engagement stone. That part was sold to us.
The marketing history nobody talks about
Here is the part that surprises people. Diamond engagement rings were not the norm until the late 1940s. Before that, only about 10 percent of engagement rings featured a diamond, and many used sapphires, rubies, or no stone at all. Then De Beers, sitting on a diamond supply and slumping post-war sales, hired the ad agency N.W. Ayer.
In 1947, a copywriter there named Frances Gerety wrote four words: "A Diamond Is Forever." As Sotheby's documents, that single line, backed by decades of placing diamonds on Hollywood stars and in films, reshaped the entire market. The campaign tied diamonds to love and permanence so tightly that by the late twentieth century, the great majority of brides expected a diamond. The price we accept today rests heavily on that story.
Lab-grown is undercutting natural prices
The newest pressure on diamond pricing is lab-grown stones, which are chemically and physically identical to mined diamonds but cost a fraction to produce. As factories scaled up, lab-grown prices fell roughly 85 percent between 2015 and 2025, according to reporting by Money citing analyst Paul Zimnisky. That flood of cheaper, identical-looking stones has dragged on natural diamond prices too, which had already softened. The "diamonds always go up" idea was never quite true, and it is less true now.
So are they worth it? The resale reality
If you mean "will it hold its money," no. A diamond loses most of its retail markup the moment you own it, and the resale market returns far less than you paid. That is true for natural stones and even more so for lab-grown ones. A diamond is a thing you buy to wear and to keep, not a financial asset. We say this plainly at the counter, because we would rather a customer spend with clear eyes than feel misled later.
Worth it, then, depends on what you want. A beautiful stone you will wear for fifty years, that carries meaning, is worth it on those terms. A stone you expect to resell at a profit is not. Browse our engagement rings or our wider ring collection and buy for the wearing, not the reselling.
Where to put your money
If the price still feels steep and you want it to buy as much beauty as possible, here is how we coach customers at the counter. Spend on cut first, because a well-cut stone of modest size will outshine a larger stone that was cut poorly. Then ease off on colour and clarity, since most flaws and faint tints are invisible to the naked eye once a stone is set and on a hand. A diamond graded slightly below the top of the scale often looks identical to the untrained eye while costing noticeably less.
Carat is where the price climbs fastest, because larger gem-quality stones are rarer. Going from a smaller stone to a larger one of the same quality can cost far more than the size difference suggests. If budget is tight, dropping a fraction of a carat frees up real money with little visible loss. And if you want maximum size for the money, a lab-grown stone or an elongated shape will stretch the budget further than chasing carat weight in a natural round.
| Factor | What it does to price |
|---|---|
| Carat (weight) | Price rises steeply with size; large stones are rarer |
| Cut | Biggest driver of sparkle; pay here first |
| Colour and clarity | Closer to colourless and flawless costs more |
| Mining cost | Real scarcity and labour add genuine cost |
| Marketing legacy | De Beers built demand that props up prices |
| Lab-grown competition | Pushing prices down across the board |
Key Takeaways
- Diamond price comes from the 4Cs (carat, cut, colour, clarity), real mining scarcity, and decades of marketing.
- Cut is the biggest driver of sparkle, so prioritise it over chasing carat weight.
- The diamond engagement ring became standard only after De Beers' 1947 "A Diamond Is Forever" campaign.
- Lab-grown diamonds, down ~85% in price from 2015 to 2025, are dragging natural prices down too.
- Diamonds are not investments. Resale returns far less than retail. Buy to wear and keep.
Frequently Asked Questions
Why are diamonds so expensive?
Diamonds are expensive because gem-quality stones are genuinely scarce and costly to mine, the 4Cs grading system prices quality precisely, and decades of De Beers marketing made the diamond the expected engagement stone. Part is real scarcity, part is manufactured demand.
Are diamonds actually rare?
Gem-quality diamonds are uncommon, since most mined diamonds are industrial grade and only a small fraction are jewellery quality. But diamonds are not as scarce as their price implies. Tightly managed supply and powerful marketing have long supported prices above what raw rarity would justify.
Did De Beers create the diamond engagement ring tradition?
Largely, yes. Before the late 1940s only about 10% of engagement rings held a diamond. De Beers' 1947 "A Diamond Is Forever" campaign, written by Frances Gerety, tied diamonds to love and permanence and made them the default within a generation.
Do diamonds hold their value or resell well?
No. A diamond loses most of its retail markup the moment you buy it, and resale returns far less than you paid. This is true for natural diamonds and even more so for lab-grown ones. Buy a diamond to wear and keep, not as an investment.
Sources
- GIA - The 4Cs of Diamond Quality
- Sotheby's - How De Beers Changed the Diamond Market With One Tagline
- Wikipedia - Mary Frances Gerety ("A Diamond Is Forever")
- Money - Diamond Prices Plunge as Lab-Grown Surge (2025)
Data sourced June 2026. If you spot something out of date, let us know and we will update the guide as the trade evolves.
Visit Vanhess
We are a family-run studio at 2929 Barnet Highway, Unit 2424, Coquitlam BC, with our own goldsmith and our own designs. We will walk you through the 4Cs in plain language and show you natural and lab-grown side by side, so you spend with clear eyes. Browse our engagement rings or call +1 (604) 653-6449 to book a time.
