Why Lab-Grown Wins Bigger on Emerald and Asscher Step Cuts

Natural emerald and asscher cuts carry the steepest clarity tax in the diamond market, and lab-grown wipes most of it out. We covered the full lab-grown vs natural pricing spread across our 14 million stone index, where the median lab-grown discount lands around 80% depending on shape. Step cuts tell a more specific story. Emerald and asscher, the two main step cut shapes, use broad open facets that expose the interior of a diamond like no other cut style. That transparency is what makes them beautiful. It's also what makes them expensive in natural, and what makes lab-grown such a sharp value play.

The headline discount on lab-grown emerald cuts is 81.0%. Asscher sits at 81.7%. Neither is the market's largest percentage gap. But headline discounts miss the point for step cuts, because the real savings compound where it matters most: in the clarity grades these cuts actually demand.

The hall of mirrors problem

Step cut diamonds use long, open facets arranged in parallel tiers. Think of it as looking down a corridor versus looking into a kaleidoscope. A round brilliant is the kaleidoscope; light fractures in every direction, scattering the view of anything inside the stone. An emerald or asscher is the corridor. Clean sightlines. No hiding spots.

This isn't subtle. Inclusions that disappear inside a round brilliant sit in plain view in a step cut. A small crystal near the table of a round might never catch your eye. That same inclusion in an emerald cut gets magnified by flat facets acting as mirrors. Visible at arm's length, sometimes across a room. Every wisp, every feather, every pinpoint becomes part of the stone's appearance, whether you want it there or not.

The consequence is financial. Natural step cuts demand higher clarity grades to face up clean. Higher clarity costs more. And the premium between grades scales sharply as you climb, adding hundreds of dollars per carat with each step up on a natural stone.

Where eye-clean kicks in

For round brilliants, the generally accepted eye-clean threshold is SI1. Plenty of SI2 rounds look perfectly clean too, depending on inclusion type and where it sits in the stone. Step cuts shift that threshold up by one to two full clarity grades.

Most emerald cuts need VS2 at minimum to appear eye-clean, and even there, placement matters enormously. A VS2 emerald cut with a cloud or crystal sitting directly under the table facet will still show it to the naked eye. Conservative buyers, and plenty of experienced ones, push to VS1 as their safety line for emerald cuts. Asscher cuts raise the bar further. Their concentric square facets create layered transparency, almost like looking into a tunnel of mirrors. Many asscher buyers won't settle for anything below VVS2.

In natural diamonds, each of those clarity jumps costs real money. Going from SI1 to VS1 adds a meaningful premium. VS1 to VVS2 is steeper, because you're competing with collectors and investors at those grades, not just engagement ring shoppers. Natural step cuts in VVS territory trade at serious premiums over their VS counterparts.

Lab-grown flips this entire calculus. High clarity is the norm in lab production, not the exception. A VVS2 lab-grown emerald cut doesn't command the rarity premium of its natural equivalent, because lab-grown VVS2 stones simply aren't rare. They're standard production output. The clarity grade you actually need for a beautiful step cut goes from aspirational to routine. That's the structural shift that headline discount percentages don't capture.

The median numbers

Our index across active listings tells the broad story:

Shape	Natural $/ct	Lab $/ct	Lab discount	Lab listings
Emerald	$2,012	$383	81.0%	586,249
Asscher	$2,292	$419	81.7%	100,285
Round	$1,970	$338	82.8%	2,137,313
Oval	$2,344	$394	83.2%	1,130,707
Cushion	$2,741	$456	83.4%	544,966

Emerald's 81.0% discount and asscher's 81.7% both sit below cushion at 83.4% and oval at 83.2%. Marquise trails the pack at 79.3%. Neither step cut dominates on headline discount percentage. If step cuts see the biggest lab-grown advantage, why don't the headline discounts reflect it?

Because these medians blend every clarity grade together. A natural emerald cut graded SI2, which few informed buyers would choose for a step cut, pulls the natural median down. Meanwhile the lab-grown median includes plenty of VS and VVS stones that don't carry meaningful premiums over lower grades. The median smooths out the very dynamic that makes step cuts interesting.

The structural advantage reveals itself when you shop within the clarity grades step cuts actually require. A natural VS1 emerald cut trades at a hefty premium over a natural SI1 emerald cut. A lab-grown VS1 costs roughly the same as a lab-grown SI1, because clarity premiums barely register in lab-grown production. That compressed clarity pricing is where the real savings live, and it's most valuable in the shapes where the eye-clean floor sits highest.

We see similar clarity sensitivity play out in fancy shapes like pear, marquise, and cushion, but the effect is sharpest in step cuts because the minimum acceptable clarity grade is higher than any other cut family.

The asscher situation

Asscher deserves separate attention. As of September 2026, lab-grown asscher sits at $419 per carat, now trading close to the broader lab cluster. Lab rounds run $338. Lab emeralds, $383. Lab ovals, $394. Lab-grown asscher carries a small premium over the others, but the gap has narrowed considerably since earlier in the year.

Supply is part of the explanation for why any premium persists. Our index holds 100,285 lab asscher listings versus 2,137,313 lab rounds. Asscher is a specialist cut, and specialist cuts carry premiums even in lab-grown. Production factors compound this. The asscher's strict symmetry requirements waste more rough during cutting, and fewer manufacturers prioritise the shape.

	Natural listings	Lab listings	Lab to natural ratio
Emerald	362,752	586,249	1.6x
Asscher	70,177	100,285	1.4x
Round	2,189,365	2,137,313	~1.0x

Lab-grown production has tilted more heavily toward both step cuts than toward rounds, proportionally. Lab asschers outnumber natural asschers by 1.4 to 1. Lab emeralds, 1.6 to 1. Lab rounds now sit at roughly 1 to 1. Manufacturers clearly see the demand, which should put downward pressure on step cut lab-grown pricing over time.

On the natural side, asscher at $2,292 per carat already sits above natural round ($1,970) and comfortably above natural emerald ($2,012). Asscher has always been the pricier step cut. The 81.7% lab discount still translates to $1,873 saved per carat. On a 2ct stone, that's close to $3,750.

Emerald tells a cleaner story. Lab-grown at $383 against natural at $2,012 means $1,629 saved per carat. And with 586,249 lab-grown listings, emerald offers buyers genuine breadth across colour and clarity grades.

What a buyer actually saves

Take a common scenario: someone shopping for a step cut engagement ring, roughly 1.5ct, in the G to H colour range, with enough clarity to face up clean. No visible inclusions. A stone they'll be proud of.

In natural, this buyer needs VS1 or better for an eye-clean emerald cut. At the natural emerald median of $2,012 per carat, a 1.5ct stone runs about $3,018 at the median across all clarity grades. But VS1 and above trade well above that median, so the real cost pushes higher. Factor in the setting, and the total spend grows fast.

In lab-grown, the same buyer can confidently select VS1 or even VVS2 without the budget strain. At a lab-grown emerald median of $383 per carat, a 1.5ct stone sits around $575. Even filtering specifically for VS1 or better in the G colour range, lab-grown emerald cuts in this tier typically land well under $1,000 total.

For asscher, the lab-grown median sits at $419 per carat, putting a 1.5ct stone around $630. The natural equivalent at $2,292 per carat pushes a 1.5ct asscher to about $3,438, and VS1 or VVS2 naturals will exceed that comfortably. The lab-grown price, by contrast, barely moves up for higher clarity.

That gap changes what's possible. It's enough to move into a higher carat weight, invest in a better setting, or simply keep the savings. Someone who would have compromised on a round brilliant, because an eye-clean natural emerald cut blew the budget, can now buy that exact emerald cut in lab-grown. Often at a better clarity grade than they'd have managed in natural. And at a fraction of the step cut diamond price.

What we're watching

Lab-grown emerald pricing is the number to keep an eye on now. At $383 per carat, it sits $45 above lab rounds at $338, and that gap has been narrowing as production scales. Lab emeralds already outnumber natural emeralds by 1.6 to 1; if production continues at this pace, that spread to round pricing compresses further. Asscher has already come down from its earlier premium to sit within the broader lab cluster.

Step cut demand appears to be running ahead of the broader market, at least by supply ratios. Whether that translates to lower prices or simply broader selection is the open question. But for anyone shopping a step cut today, lab-grown isn't just the cheaper option. It's the one that lets you buy the clarity the cut actually requires.