Are you overpaying for a lab-grown diamond?

Marketed as an alternative to mined diamonds, lab-grown stones are growing in popularity among engaged couples, taking some of the shine from mined or “natural” diamonds, which have traditionally dominated the market.

When Toronto residents Daniel Ng and Olivia Chan were ring-shopping in 2024, choosing a lab-grown diamond was an easy decision, largely because of the significant price difference compared to a natural stone. 

Experts say a lab-grown diamond can cost 90 per cent less than its natural equivalent. 

“The tide has shifted. Like, more people are going with … the lab-grown,” Ng said.

Industry experts say lab-grown diamonds are becoming cheaper to make and more widely available, and confirm that more young couples are going with that option. But a Marketplace investigation found that virtually identical lab-grown diamonds are being sold at vastly different prices, raising questions about whether some consumers are paying far more than they need to.

CBC journalists bought two lab-grown diamonds, one from leading online jewelry retailer Blue Nile and the other from a vendor on the online marketplace Alibaba.com.

Both diamonds had the same features: one carat, D-colour, ideal cut, VS1 clarity and round shape. 

The Blue Nile diamond cost $1,639.23 Cdn, including shipping and taxes. The diamond purchased from Alibaba cost $228.86, all-in. 

Marketplace reviewed prices at other online retailers and found comparable stones listed for as much as $1,500 before fees and taxes.

Ng said the price he paid for Chan’s ring felt like a good deal. He proposed with a D-colour, 2.33-carat, VVS2 lab-grown diamond in May 2025, and said the entire ring cost less than $6,000 Cdn.

The couple was shocked at the cost of the Alibaba diamond.

“We had no idea,” Chan said. 

Why prices for similar lab-grown diamonds can vary

Paul Zimnisky, a U.S.-based diamond industry analyst and independent board member of Lipari Mining Ltd., said he has seen price gaps like this, warning they could create “credibility problems” for the industry.

“I think there’s definitely been an incentive for jewellers to sell the lab-grown diamond, because the profit margin potential is much higher,” he said. “The sales pitch has been, you know, ‘This is still a diamond, and instead of spending $6,000 [US, on a ring], you could get this for $1,000 or $2,000.’”

He said “it doesn’t change the fact” that the seller probably bought the lab-grown diamond “at wholesale for 75, 85, 95 dollars.” 

“With the man-made diamond, all of them are good-enough quality for jewelry, so they’ll just keep producing them,” he said. “It’s an economy-of-scale business, so the more they produce, the lower the per-unit cost, and this is why the price is dropping so precipitously.”

While Zimnisky said markups are a normal part of doing business, he thinks some retailers are pricing lab-grown diamonds “way, way above where they should be.”

“A stone with the exact same characteristics could be sold at [a] very different price,” he said. “You could find the same diamond for $150 [US] or for $1,500.”

Verifying the diamonds

Both lab-grown diamonds that Marketplace bought came with a report from the International Gemological Institute (IGI) describing their characteristics. 

To eliminate doubts about the Alibaba purchase, Marketplace sent the diamond back to IGI to verify its original certificate, as counterfeiting is a known issue in online marketplaces. 

The certificate was confirmed as legitimate, so journalists then turned to Eddy and Allan Young, two brothers who are accredited jewelry appraisers, to determine whether the Blue Nile and Alibaba diamonds were truly equivalent in quality.

At their Toronto office, Gem Review Inc., the brothers put both diamonds under the microscope. Allan screened the stones to verify their physical characteristics and Eddy completed the formal appraisal.

“Identical,” Eddy Young said. “No difference.”

He gave both diamonds the same estimated retail value: $1,925 Cdn.

When Marketplace told him the cost of the two purchases, he was unsurprised by the variance.

“The one you bought from Alibaba, you cannot normally get it from a local jeweller locally for that price,” he said. “I do know that that’s how much they are when you buy directly from [the manufacturer].”

Young said many consumers still don’t realize how cheaply lab-grown diamonds can be produced in manufacturing hubs such as China and India.

Marketplace also consulted Greg Thompson of Gem Experts Inc. and obtained a second appraisal for both diamonds. The diamonds were still valued at the same price, but this time quoted at a retail price of $900.

What the industry says

Marketplace asked Blue Nile’s parent company, Signet Jewelers, why its diamond cost significantly more than the Alibaba diamond, despite its almost identical features.

Signet declined an interview but said in a statement that “customers consistently buy Blue Nile because of the brand’s reputation, proven track record and trusted quality. Our customers have confidence knowing they are buying a product backed by experience and trust.”

WATCH | Gem expert explains difference between natural and lab-grown diamonds:

Diamond expert compares natural and lab-grown stones

Marketplace co-host Asha Tomlinson watches as appraiser Allan Young screens a lab-grown diamond.

The company said they are “proud to have strong sourcing standards as well as ethical and sustainable production and procurement processes,” and the diamonds sold by Blue Nile are from vendors “who are held to strict annual reporting standards.”

Marketplace also brought questions about inconsistent pricing to the Canadian Jewellers Association (CJA), an industry group that calls itself “the voice of the Canadian jewellery industry.” 

The CJA also declined an interview but said in a statement that it does not get involved in members’ pricing decisions, calling it “impossible to set uniform guidelines for the industry.” 

It also noted it does not “represent all jewellers in Canada.”

The CJA said it encourages members to “give fair and impartial information so that the consumer can make an informed choice.”

How to shop smarter

Eddy Young said some consumers may hesitate to buy directly from foreign manufacturers and  encouraged shoppers to take precautions.

He advises checking reviews, paying by credit card or PayPal, and having diamonds appraised to confirm their authenticity.

Young said lab-grown diamonds are getting “bigger and cheaper, so there’s no reason to spend so much money on [an] engagement ring.”

Zimnisky predicts general prices for lab-grown diamonds will eventually fall closer to wholesale levels.

Chan and Ng said they wish they had done more research, but are glad to be better informed now about the pricing.

“My thought is just [that] I want a diamond necklace now for the wedding,” said Chan of the upcoming celebration this summer. She said they plan to shop around and ask more questions for future purchases. 

Both said they would like to see more consistent pricing across the industry.

“You don’t want to spend more than you should,” Ng said.

“I think it’s good that it’s more accessible to everyone,” Chan added. “No gatekeeping diamonds. People deserve to have what they want at the prices that it can be produced at.”