Diamond prices in October 2026: natural slides, lab-grown edges up

Natural diamonds fell to a median of $2,202.24 USD per carat in October 2026, down 6.71% from $2,360.61 the month before, while lab-grown went the other way, rising 2.17% to $462.37. That pulls the natural to lab ratio in to 4.8 to 1, from 5.2 to 1 a month earlier, and every figure in this post comes straight from the Caratlytics October 2026 release. A 6.71% monthly drop in natural isn't something I wave through without asking where it came from. So that's what we're doing here.

Two markets, opposite directions

On the surface, nothing happened. Our overall median sat at $812.75 per carat against $813.31 in September, a move of 0.07%. Flat as a tabletop.

But that flat line is two segments cancelling each other out. Natural lost $158.37 per carat at the median. Lab-grown gained $9.83. And because the index observed 2,297,795 lab-grown listings against 1,297,040 natural ones this month, the overall figure leans heavily towards the lab-grown end of the market, which is why it barely flinched.

Segment	October median	September median	Month on month	Lower quartile	Upper quartile	Listings observed
Natural	$2,202.24	$2,360.61	down 6.71%	$1,533.33	$3,746.50	1,297,040
Lab-grown	$462.37	$452.54	up 2.17%	$285.44	$773.26	2,297,795
Overall	$812.75	$813.31	down 0.07%	$366.19	$1,841.72	3,594,842

The natural premium over lab-grown still stands at 376.3%, so nobody should read this as the two markets converging in any meaningful way. Natural is still a different purchase entirely. What's changed is the direction of travel, and for natural buyers that direction was helpful this month.

Step cuts took the hit

Nine of ten natural shapes fell. Princess led the way down at 8.2%, with emerald right behind at 8.1%. Oval dropped 7.2% and round 6.9%, which matters because those two shapes carry a huge share of engagement ring demand.

The lone natural riser was radiant, up 0.3% to $3,108.17 per carat. It's already the most expensive natural shape in our index, and it simply refused to move. Pear (down 2.3%) and cushion (down 2.5%) were the next most resilient.

Shape	Natural	Natural change	Lab-grown	Lab-grown change
Round	$2,124.21	down 6.9%	$425.00	up 1.7%
Oval	$2,511.55	down 7.2%	$478.64	up 3.3%
Cushion	$2,880.87	down 2.5%	$555.04	up 4.5%
Princess	$1,991.13	down 8.2%	$458.23	down 2.9%
Emerald	$2,108.85	down 8.1%	$467.94	down 0.4%
Pear	$2,260.80	down 2.3%	$468.91	up 1.3%
Marquise	$2,176.86	down 4.2%	$504.55	up 1.6%
Radiant	$3,108.17	up 0.3%	$489.06	down 0.7%
Asscher	$2,432.10	down 3.0%	$494.83	up 1.5%
Heart	$2,289.11	down 3.7%	$428.16	up 1.4%

Lab-grown told nearly the opposite story. Cushion climbed 4.5% to $555.04, now the dearest lab-grown shape per carat. Oval rose 3.3% and round 1.7%. The fallers were princess (down 2.9%), radiant (down 0.7%) and emerald (down 0.4%).

Two things catch my eye. Oval fell 7.2% in natural and rose 3.3% in lab-grown, the widest split of any shape this month. And princess fell meaningfully in both segments, the only shape to do so. If you've been eyeing a natural princess, the market has quietly moved in your favour; at $1,991.13 per carat it's now the cheapest natural shape in the table.

What the grading lab tells you (and what it doesn't)

Certificate splits are where people draw the wrong conclusions, so let me be careful.

Grading lab	Natural	Lab-grown
GIA	$2,263.37	$938.85
IGI	$1,784.60	$443.74
HRD	$2,971.56	$458.61
GCAL	n/a	$980.68
EGL	$3,337.28	n/a
Other	$1,819.52	$708.00

A GIA natural median of $2,263.37 against an IGI natural median of $1,784.60 is a gap of $478.77 per carat. In lab-grown, GIA sits at $938.85 and IGI at $443.74, a gap of $495.11. Tempting to call that the price of a GIA certificate. It isn't.

These are medians across very different inventories. IGI grades the bulk of lab-grown stock, so its median reflects the whole market. GIA and GCAL lab-grown stones are a smaller, more selective pool, and their medians reflect what retailers chose to send them, not a premium on an identical stone. Use these numbers to understand the mix, not to price a specific diamond.

And EGL at $3,337.28 for natural? Highest median in the table. I'd treat that with real caution. EGL paper has a history of grading more generously than GIA, so a high per carat price on an EGL certificate tells you what sellers are asking, not what the stone is worth. If you're buying natural, I want a GIA report in your hand.

Same stone, very different prices

This is the section I care about most, because it's where buyers lose real money without ever knowing it.

Our index tracks 144 active retailers and 50,205,086 active listings, covering 12,600,976 certified diamonds. Of those, 4,772,681 are listed at more than one retailer, which means the same stone, with the same certificate number, carries more than one price tag.

Segment	Stones at more than one retailer	Median spread	Average spread	Total spread (USD)
Natural	1,566,683	77.1%	97.6%	$3,678,270,038
Lab-grown	1,448,323	215.4%	203.7%	$2,234,172,277

Read the lab-grown row twice. A median spread of 215.4% means the typical lab-grown stone listed at several retailers carries wildly different asking prices depending on where you find it. And because the median sits above the average, this isn't a few outliers dragging the number up. It's the normal state of the lab-grown market.

Natural is tighter but hardly tidy: a median spread of 77.1% on a category where a single stone can run to five figures, and a total spread of $3,678,270,038 across those stones. We break this down further in our cross-retailer analysis, and honestly, it's the single most useful page on the site for anyone about to spend money.

Where I'd spend this month

If you're buying natural, October handed you a window. Princess and emerald fell 8.2% and 8.1%, and at $1,991.13 and $2,108.85 per carat they're the two cheapest natural shapes we track. Natural round, down 6.9% to $2,124.21, is also worth a look if you've been waiting for a softer moment. I'd skip natural radiant unless you're set on it; it's the one shape that gave you nothing this month.

In lab-grown, the momentum runs against cushion and oval. Cushion is up 4.5% and oval 3.3%, so if you love a lab-grown cushion you're paying more than you would have a month ago. Round ($425.00) and heart ($428.16) remain the cheapest lab-grown shapes per carat, and princess eased 2.9% to $458.23.

Our shape data doesn't split by size, so check our 1 carat breakdown before you set a budget. Price per carat jumps at the weight thresholds, and a stone just under a round number often gives you the look for noticeably less.

But my honest advice applies whatever you buy. A 2.17% monthly move in lab-grown is pocket change next to a 215.4% median spread. Get the certificate number, search it, and compare every retailer listing that stone. The monthly index tells you which way the tide is moving. The spread tells you whether you're about to overpay badly.

What I'm watching in November

First, whether natural keeps falling. One month of 6.71% could be a shift in which stones were listed and sold, not a true repricing. A second consecutive drop of that size would be genuinely significant, and I'd say so loudly.

Second, the ratio. It moved from 5.2 to 1 down to 4.8 to 1 in a single month. If it compresses again, the conversation about natural versus lab-grown value gets more interesting for mid budget buyers.

Third, lab-grown cushion. A 4.5% monthly rise in a segment where most of the news is usually about falling prices is unusual, and I want to see whether it holds or whether it was a one off change in inventory mix. You can follow every release on our diamond price index page.

And the number I'll keep watching most closely isn't a median at all. It's that lab-grown spread of 215.4%.