The Same Diamond, Three Times the Price

A natural 1.51ct D colour princess cut is listed right now for $2,030. The median price per carat for that category is $7,823. That's 83% below what most retailers charge for the same specs. It won't last, and whoever finds it first gets a stone that would cost $11,800 almost anywhere else.

This is what the market looks like in April 2026: massive price gaps hiding in plain sight, particularly in lab-grown fancy shapes and natural princess cuts. The retailers with the best prices aren't always the ones with the biggest marketing budgets. And the categories where you'll save the most aren't the ones getting attention on social media.

Lab-grown fancy shapes are wildly mispriced

The lab-grown market has 27.6 million active listings right now, averaging $1,193 per stone. Prices dipped 0.6% over the past 30 days while natural diamonds climbed 6.6%. That divergence is old news. What's not old news is just how wide the retailer spreads have become on specific shapes.

Lab-grown radiant cuts have an average cross-retailer spread of 254%. That means the most expensive listing for a given stone is, on average, 2.5 times the cheapest. Emerald cuts aren't far behind at 242%. These aren't different diamonds with slightly different specs. These are identical stones, same certificate number, same lab, same measurements, priced wildly differently depending on where you shop.

Shape (Lab-Grown)	Avg Cross-Retailer Match Rate	Avg Price Spread
Radiant	49.1%	254%
Emerald	48.6%	242%
Pear	45.1%	227%
Oval	47.8%	216%
Round	62.4%	214%
Cushion	46.6%	214%
Heart	51.2%	194%
Marquise	48.0%	190%

Round lab-grown diamonds have the highest match rate at 62%, meaning nearly two thirds of round lab-grown stones appear at multiple retailers. But the spread is "only" 214%. Radiant and emerald cuts match less frequently, yet when they do match, the price gaps are brutal. If you're buying a lab-grown emerald or radiant cut and you don't comparison shop, you're statistically likely to overpay by more than double.

The advanced search is the fastest way to surface these. Sort by score and the algorithm already factors in cross-retailer pricing.

Natural princess cuts are the buy of the month

Two separate natural princess cut diamonds, both 1.51ct D colour, are sitting at $2,030 and $2,410 respectively. The category median is $7,823 per carat, which puts a typical 1.51ct D princess at roughly $11,800. These two stones are 80 to 83% below that.

Princess cuts have always been undervalued relative to rounds, but this level of discount on D colour naturals is unusual. The natural to lab price gap on princess cuts is also the narrowest of any shape at 77.9%, compared to 87.8% for marquise or 86.1% for emerald. That means natural princess cuts are already priced closer to lab-grown territory than any other shape. For buyers who want natural but don't want to pay the typical natural premium, princess is the shape to watch.

The broader natural market moved up $25 per stone on average over the past seven days. That's a modest weekly gain, but it follows a 30 day trend of +6.6%. Lab-grown went the other direction, down 0.6% over 30 days. The scissors are opening.

Where the big money moved this week

The top movers in natural diamonds this week were all large stones, 4ct and above. These aren't relevant for most engagement ring buyers, but they tell you something about where dealer confidence is flowing.

Category	Median Price/ct	7 Day Move/ct	Listings
Asscher 5 to 9.99ct D-E VVS (Natural)	$47,593	+$2,325	38
Marquise 5 to 9.99ct F-G VS (Natural)	$34,936	+$2,194	45
Round 4 to 4.99ct D-E VVS (Natural)	$41,514	+$1,722	630
Oval 5 to 9.99ct D-E VVS (Natural)	$43,972	+$1,691	146
Oval 4 to 4.99ct D-E VVS (Natural)	$32,731	+$1,618	69

The round 4 to 4.99ct D-E VVS category is the one worth paying attention to. With 630 listings, it's liquid enough to be a real market signal rather than just a few stones moving around. A $1,722 per carat weekly gain on a 4ct stone is nearly $7,000 in a week. Interestingly, that same category dropped $21 per carat over 30 days, so this week's spike could be a correction or the start of a new leg up. Either way, if you've been considering a 4ct+ round in high colour and clarity, the 30 day dip may be closing.

No natural categories showed meaningful declines this week. That's notable on its own. In a market with 14.7 million natural listings, a week with zero falling categories suggests broad, if shallow, upward pressure.

The retailers actually worth your time

Retailer pricing data tells a clear story about who's competing on price and who's relying on brand.

Blue Nile's average markup sits at negative 12.5% relative to cross-retailer medians, across 29,380 active listings. Lukhi Diamond runs even lower at negative 15%. On the other end, Temple and Grace averages a 168% markup on 690 listings. Grown Brilliance sits at 28% above median with 24,096 listings.

James Allen carries the largest inventory at 136,399 active listings but runs a 53% average markup. That's the trade: widest selection, higher prices. If you know exactly what you want and James Allen has a unique stone, fine. But if the same stone exists at Blue Nile (and with a 62% cross-retailer match rate on rounds, it probably does), you're paying a 50%+ premium for the privilege of buying from JA.

Grown Brilliance is the interesting one. At 28% above median, they're not cheap, but they carry 24,000 lab-grown listings and their inventory occasionally surfaces stones that score well on our quality metrics despite the markup. The selection breadth means they sometimes have cuts and specs that simply aren't available elsewhere.

Supply shifts signal what's coming

Lab-grown round 1.50 to 1.99ct listings surged by 2,603% in weekly supply change, though the absolute numbers (183 new, 198 delisted) show heavy churn rather than a true flood. That category has 3,109 active listings, and the turnover suggests retailers are actively rotating inventory. Prices should stay flat or drift down.

Natural cushion cuts in the 0.50 to 0.74ct range saw a 2,467% supply bump (42 new against 27 delisted). That's genuine net new inventory. Natural pears in the 1.00 to 1.24ct range added 77 new listings but also lost 77, so it's pure churn at 1,470 total. The cushion supply story is real; the pear story is noise.

For buyers, new supply in natural cushions under 0.75ct means more selection and slightly more pricing pressure. These are popular secondary stones for three stone rings and halo settings, so timing a purchase in the next few weeks makes sense while selection is expanding.

The lab-grown gap everyone should understand

The average lab-grown diamond costs 83% less than its natural equivalent. That number has been widely reported. What's less discussed is how much that gap varies by shape.

Marquise cuts have the widest gap at 87.8%. A natural marquise averages $8,017; its lab-grown equivalent averages $978. Princess cuts have the narrowest gap at 77.9%, with naturals at $5,110 and lab-grown at $1,127. Rounds sit at 79.8%, the second narrowest.

If you're a lab-grown buyer, marquise and pear (86.7% gap) give you the most dramatic savings relative to natural. If you're a natural buyer looking for the shapes where lab hasn't completely undercut you on price, princess and round are your best bets, though "best" is relative when we're still talking about a 78 to 80% premium.

Square radiant cuts deserve a mention. The natural to lab gap there is just 71.1%, the lowest of any shape. Natural square radiants average $1,500, lab-grown just $433. These are smaller, less common stones, but if you want something distinctive at a reasonable price in either origin, square radiants are quietly underpriced across the board.

What to do this week

The immediate opportunities come down to three categories.

First, natural princess cuts in the 1.50 to 1.99ct range. Two D colour stones are priced 80 to 83% below median right now. Even if those specific listings sell before you read this, the category as a whole is running well below where rounds and ovals trade. Princess has been unfashionable for a few years, which is precisely why the value is there.

Second, lab-grown radiant and emerald cuts if you comparison shop. Spreads of 242 to 254% mean the difference between a good deal and a terrible one is literally which retailer you click. Use the cross-retailer view and sort by overall score. The algorithm already penalises overpriced listings when the same stone exists cheaper elsewhere.

Third, watch the natural 4ct+ round D-E VVS category. The $1,722 per carat weekly gain reversed a 30 day slide. If it holds through next week, that's a genuine sentiment shift in the high end natural market. If it reverses, it was noise. Either way, the next seven days will tell us something.

Lab-grown prices are essentially flat. Natural prices are gently rising. The spread between origins continues to widen. None of this is dramatic enough to change your buying timeline. But if you were waiting for a signal to start seriously comparing stones, 42 million active listings and price gaps measured in hundreds of percent should be signal enough.