Lab diamonds drive bigger, cheaper rings for "engagement season"

'Tis the season to put a ring on it — and thanks to lab-grown diamonds, those rings are bigger and cheaper than ever.

Why it matters: Lab diamonds continue to reshape the engagement ring market, with the prices of all diamonds dropping and more fingers dripping in multiple carats.

By the numbers: A natural 3-carat diamond could cost an average of 16 times the cost of a lab-grown version, according to data from independent diamond industry analyst Paul Zimnisky.

• The Knot's latest study found more than half of engaged couples (52%) had rings with lab-grown stones — a first for the annual survey.
• And the stones went from an average of 1.5 carats in 2021, to 1.7 carats in 2024. According to Zimnisky, demand has particularly spiked for 2- to 3-carat natural diamonds and 3- to 5-carat lab diamonds.

Meanwhile, December (and Christmas Day, specifically) remains the most popular time of year to pop the question, per The Knot.

• It's part of "engagement season" which goes from Thanksgiving to Valentine's Day, when The Knot says almost half of couples get engaged.

Between the lines: The most reliable way to know whether a diamond was mined is with a report from an authority like the Gemological Institute of America.

• To the naked eye, lab and natural diamonds look nearly identical — even gemologists need special instruments to tell them apart — though Zimnisky says that most lab diamonds lack the yellow tint that natural diamonds have from the presence of trace nitrogen.

What they're saying: "I think we will eventually get to a point where most lab diamonds sell for under $1,000," Zimnisky tells Axios.

What we're watching: Vintage, old mine cut diamonds have gotten more popular — and can be replicated in lab versions.

Catch up after the closing bell on the day's biggest business stories. With Nathan Bomey