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3 Carat Lab-Grown Diamond Engagement Rings
27 pieces
“Start with a beautiful ring on a great band, and think about the wedding bands that go with it.” Trax, at the jewelry store on 47th Street
27 rings, each with a lab-grown center of 3 to 3.6 carats. Ten say the center is IGI certified.
The 3 carat marquise in 14K sold most in the year, 61 rings. The elongated cushion Astral came next, 39.
Every ring here holds a 3 carat lab-grown diamond center, some just over, most graded E to G in color and VS to VVS in clarity. The shapes are oval, cushion, emerald, marquise, pear, princess, radiant and round, set as solitaires, hidden halos, pavé bands and bridal sets, in 14K or 18K gold.
14K Gold Marquise Lab-Grown Diamond Engagement Ring 3 CT 71345
14K
18K Gold Oval Lab Grown Diamond Solitaire Engagement Ring 68285
18K · 1.6 mm
14K Gold Astral 3 Carat Cushion Cut Lab-Grown Diamond Engagement Ring 71303
14K · 1.8 mm
14K Gold 3 Ct Mirabella Pear Lab-Grown Diamond Engagement Ring 71607
14K
Pick the center stone
Want a carat or a shape we don’t show?
Our team texts back 10 AM to 10 PM ET; later texts are answered the next day.
14K Gold Oval Lab-Grown Diamond Engagement Ring 3 Ct 71793
14K
14K Gold Marquise Cathedral Pavé Lab-Grown Diamond Engagement Ring 69649
14K · 1.7 mm
14K Gold Willow Hidden Halo Lab-Grown Diamond Engagement Ring 71137
14K · 2.3 mm
14K Gold Rosaline Lab-Grown Diamond Engagement Ring 71499
14K · 2 mm
14K Gold Radiant Cut Pavé Lab-Grown Diamond Engagement Ring 68633
14K · 2 mm
14K Gold Clara Emerald Engagement Ring with Lab-Grown Diamonds 70982
14K · 1.5 mm
18K Gold Elongated 3 Carat Cushion Lab-Grown Diamond Solitaire Engagement Ring 68640
18K · 2.3 mm
14K Gold Radiant Cut Lab-Grown Diamond Engagement Ring with Hidden Halo 70117
14K · 1.8 mm
18K Gold 3 Ct Round Lab-Grown Diamond Engagement Ring with Hidden Halo 71519
18K · 1.8 mm
14K Gold Diana Old Mine Cushion Lab-Grown Diamond Engagement Ring 71670
14K · 2 mm
14K Gold Solitaire Round Brilliant Lab-Grown Diamond Engagement Ring 70119
14K
18K Gold Princess Cut Lab-Grown Diamond Engagement Ring Set 68836
18K
14K Gold Crescent Pavé Lab-Grown Diamond Engagement Ring 70946
14K · 1.8 mm
18K Gold Trilogy Cushion Glow Lab-Grown Diamond Engagement Ring 70688
18K
14K Gold Solitaire Emerald Lab-Grown Diamond Engagement Ring 70115
14K
14K Gold 3 Ct Oval Lab-Grown Diamond Engagement Ring with Hidden Halo 70113
14K · 1.8 mm
How big it looks at 3 carats: a round is about 9.4 mm across, an oval about 11.5 by 8.5 mm, a cushion about 8 mm across. A listing’s own measurements settle it.
Carat size chartWhen you have it: In-stock items usually ship within 2 to 5 business days. A made-to-order ring's own page gives its ship time.
Buyer's guide
How to choose a 3 carat lab-grown diamond engagement ring
The shape that shows 3 carats best, then the lab report, setting, gold and her size
Every ring here holds a lab-grown center of about 3 carats, so the choice that matters is the shape. A marquise or an oval spreads that weight long and looks biggest on the hand, while a round or a princess sits smaller and deeper. Most rings bought were a marquise or a cushion in 14K gold. Then check which paper comes with the center, and settle her size, because a resized ring is final.
Four picks from this page
14K Lab-Grown Marquise Engagement Ring, 3 ctSold most in the year, 61 rings: an E VS1 marquise, small round side diamonds, IGI report.
14K Astral Elongated Cushion Ring, 3 ct39 in the year: an F VVS2 cushion, its halo hidden under the stone, pavé on the shoulders.
18K Lab-Grown Oval Solitaire Ring, 3 ct24 in the year: a single F VVS oval held in prongs, on 18K yellow, white or rose gold.
14K Clara Emerald Cut Engagement Ring, 3 ct15 in the year: an F VS1 emerald cut flanked by baguette and emerald-cut side stones, IGI.
Shapes: how big a 3 carat center looks in each, the rings here, the IGI line and the share of rings bought
| Shape | Rings | Face-up at 3 ct | IGI report | Share bought |
|---|---|---|---|---|
| Marquise | 3 | 15 x 7.5 mm | 3 of 3 | 40 percent |
| Cushion | 5 | 9.5 x 8 mm | 2 of 5 | 25 percent |
| Oval | 6 | 11.5 x 8.5 mm | 1 of 6 | 12 percent |
| Emerald cut | 4 | 10 x 7 mm | 2 of 4 | 9 percent |
| Pear | 2 | 12.5 x 8 mm | 1 of 2 | 7 percent |
| Radiant | 2 | 9.5 x 7.5 mm | 1 of 2 | 6 percent |
| Round | 3 | 9.4 mm | none | 1 percent |
| Princess | 2 | 8 mm square | none | none |
Every count on this card is from the 27 rings live here on October 13, 2026 and what this page sold in the year to October 12, 2026; prices are on the listings. Face-up sizes follow our diamond size chart for a 3 carat stone, with the cushion taken long, and are not a measure of any one ring. Each ring's shape is the one its title names, else its center cut.
Questions we get in the store
How big is a 3 carat diamond on the hand?
A round of 3 carats measures about 9.4 mm, a little over half as wide as the finger it sits on. Cut long, the same weight shows more, and a 3 carat marquise runs about 15 mm tip to tip.
Is a 3 carat lab-grown diamond a real diamond?
Yes. Grown or mined, it is one carbon crystal with the same hardness and fire, and a gem lab grades both with the same letters. Only the birthplace changes. Each of these centers is lab-grown, and every title names it.
Do 3 carat lab-grown engagement rings come with a certificate?
Ten of these rings say the center diamond is IGI certified, and they made up nine in ten rings bought in the year. Where a listing has no IGI line, ask us in the live chat whether a lab report comes with it.
More questions we get
What shape is most popular for a 3 carat engagement ring?
Here it was the marquise, about four in ten rings bought in the year, then the cushion, nearly always the elongated kind. Both read long on the finger, so the 3 carats look bigger still. Marquise engagement rings.
What color and clarity should a 3 carat lab diamond have?
E or F color with VS clarity or better, which is what nearly every center here carries. Every ring bought in the year had an E or F center. The three G centers read a shade warmer, most of all in white gold.
Are the side diamonds lab-grown too?
On eleven rings the listing says so. Five others set the grown center between natural side diamonds, both princess rings among them. Five more name no origin for their small stones, so ask the desk before you choose one of those.
How can I learn her ring size and keep the proposal secret?
Borrow a ring from her ring finger for an hour and take it to a jeweler, or quietly ask a friend or relative who will not tell her. All 27 rings run from 5 to 7.5 in half sizes, most from 4 to 9.
Can a 3 carat engagement ring be returned?
Yes, unless it was resized or made to her size, which is final. Others come back unworn and unaltered with the desk's okay, by day fourteen after delivery, on our insured label. Return postage and the five percent restocking fee come off (refund policy).
How much does a 3 carat lab-grown engagement ring cost?
Each listing prints its own price. It moves with the shape, the grades, the side diamonds and the gold. For a shape not shown here, ask in the live chat first, or call or text 212-872-9692 from 10 AM ET.
