Lab-grown diamonds have transitioned from a niche alternative to the dominant choice for engagement ring center stones, according to new insights from San Diego jewelry designer Carl Blackburn. At his La Jolla studio, C. Blackburn Jewelers, Blackburn says couples now routinely arrive at consultations already considering or specifically requesting a lab-grown diamond, a marked change from just a few years ago when many were uncertain about the category.
The shift is backed by national data. 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 once-novel option has become mainstream. For Blackburn, the appeal often starts with value: because lab-grown diamonds typically cost substantially less than comparable natural stones, buyers can opt for a larger center stone, better color or clarity, or redirect more of their budget toward custom 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." That flexibility is particularly consequential in the realm of custom engagement rings, where the center stone's proportions dictate the entire architecture of the piece. The Knot study also found that lab-grown center stones averaged 2.0 carats, compared with 1.6 carats for natural stones, a difference Blackburn says can open up new design possibilities.
"A larger diamond can completely change the architecture of a design," he said. "When clients have more flexibility with the center stone, it gives us more possibilities for the ring surrounding it." The implications extend beyond aesthetics. Lab-grown diamonds share essentially the same chemical composition, crystal structure, hardness and optical properties as natural diamonds; their principal difference is origin. That distinction matters to buyers motivated by price, by a desire to avoid traditional mining, or by greater transparency about how a stone was produced.
Blackburn continues to design rings with natural diamonds for clients who value rarity, geological history, family significance or tradition. "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." The broader significance of the trend lies in how it is reshaping the engagement ring market: as lab-grown stones become the default, the conversation has moved from whether they are acceptable to what couples can create with them. "People aren't necessarily asking, 'Is it okay to buy lab-grown?' anymore," Blackburn said. "They're asking what size, shape and design they can create with it." For couples navigating that choice, Blackburn emphasizes that the stone is only one element. "Whether the diamond came from the Earth or a laboratory, it is only one part of the engagement ring," he said. "The meaning comes from the people, their story, and the design we create around it." More information about the studio's approach is available at CarlBlackburn.com.
