Lab-grown diamonds have transitioned from an alternative to a mainstream preference for engagement rings, according to San Diego jewelry designer Carl Blackburn, who reports a marked shift among couples visiting his La Jolla studio. The change is not merely anecdotal: The Knot's 2026 Real Weddings Study found that lab-grown diamonds accounted for 61 percent of engagement ring center stones purchased by couples in 2025, confirming that the category now dominates the market.
For Blackburn, the shift is evident in the questions clients ask. "Just a few years ago, people would come in asking whether they should even consider a lab-grown diamond," he said. "Now, many couples already know it is an option and want to see what their budget can achieve with one." That evolution matters because it signals a broader normalization of a category that once carried uncertainty for buyers.
The implications extend beyond preference into purchasing power. Because lab-grown diamonds typically cost substantially less than comparable natural stones, buyers can allocate funds differently—choosing a larger center stone, upgrading color or clarity, or investing more in design and craftsmanship. "For some couples, it means choosing the two- or three-carat diamond they really wanted instead of compromising on size," Blackburn said. "For others, it means putting more of their budget into creating a completely custom ring." This flexibility is particularly consequential for custom engagement rings, where the center stone's proportions influence the entire design.
The size effect is measurable. The same Knot study found that lab-grown diamond center stones averaged 2.0 carats, compared with 1.6 carats for natural stones. "A larger diamond can completely change the architecture of a design," Blackburn said. "When clients have more flexibility with the center stone, it gives us more possibilities for the ring surrounding it."
Motivations for choosing lab-grown vary. Some couples are driven by price, while others prefer a diamond that does not require traditional mining or want greater transparency about how their stone was produced. Lab-grown diamonds share essentially the same chemical composition, crystal structure, hardness, and optical properties as natural diamonds; their principal difference is origin.
Blackburn continues to design rings with natural diamonds for clients who value rarity, geological history, family significance, or traditional appeal. "There are good reasons someone might choose a natural diamond, and there are good reasons someone might choose lab-grown," he said. "What matters is understanding what you are buying and choosing the stone that makes sense for you."
What has changed most, Blackburn says, is the conversation itself. Couples are no longer asking whether lab-grown is acceptable; they are asking what size, shape, and design they can create with it. That shift has implications for the jewelry industry, which must adapt to buyers who are better informed and more focused on design possibilities than on category doubts. For those exploring options, Blackburn's studio provides consultations through CarlBlackburn.com.
"Whether the diamond came from the Earth or a laboratory, it is only one part of the engagement ring," Blackburn said. "The meaning comes from the people, their story, and the design we create around it."
