3 Carat Diamond Ring

Design the Ideal 3 Carat Diamond Ring - Explore our popular and modern-classic ring styles to find the perfect 3 carat diamond that completes your vision.

Scroll through our diamond rings designs to find your dream 3ct diamond engagement ring. You can use the filters on the left to navigate through the options we have available.

Search through our diamond inventory, featuring over 100,000 natural loose diamonds and lab-gown diamonds, meaning you can find the perfect diamond for your ring, no matter your budget.

All our loose diamonds are available to view in our London Mayfair showroom. Our workshop is located in Hatton Garden, and all our jewellery is handmade in-house. Simply book an appointment or call us now!

Exploring 3 Carat Diamond Rings

A 3 carat diamond ring is a bold, celebrity-favourite engagement ring size. A round brilliant 3 carat diamond measures approximately 9.3 mm across, an oval 10.5×7.4 mm, a princess cut 7.6 mm square, an emerald cut 9.3×7 mm, a cushion 8.2×8.2 mm and a pear or marquise around 11.5×7.6 mm. On the hand it reads immediately as "big" on any hand; Meghan Markle, Kim Kardashian and countless others wear rings in this weight range.

At Rêve Diamonds we design and hand-set every 3 carat diamond ring in our London workshop. Our 3 ct rings are available in classic solitaire, hidden-halo, three-stone, split-shank and bezel settings, in 18k white gold, yellow gold, rose gold and platinum. Choose your diamond first from our inventory of over 200,000 GIA-certified diamonds — lab-grown from around £3,950 and natural from around £18,500 — and we build the ring around it.

Timeless and Contemporary Designs

The setting is what turns a 3 carat diamond into a ring you want to wear every day. A slim four-claw solitaire keeps the focus entirely on the stone and lets the most light in from underneath, so the diamond reads even larger. A hidden halo tucked under the crown adds sparkle without visual bulk. A three-stone design flanks the centre with two smaller side stones for a bold, symmetrical silhouette.

Popular shapes at 3 carats: round brilliant for maximum fire and traditional appeal, oval for a hand-lengthening finger silhouette, emerald and Asscher for a clean, understated Art Deco look, and cushion and elongated cushion for a soft, romantic sparkle. Fancy shapes — marquise, pear, radiant — read even larger than a round of the same weight because their footprint is bigger.

Certified and Ethically Sourced

Every 3 carat diamond we sell — natural or lab-grown — comes with a full GIA or IGI grading report covering the 4Cs: cut, colour, clarity and carat weight. Natural stones are Kimberley Process certified and traceable to origin. Lab-grown 3 ct diamonds are CVD or HPHT, chemically and optically identical to mined diamonds, and typically 60–70% less than a natural of the same specification.

Custom-Made for You

If you can't find the exact 3 carat diamond ring you have in mind, we build bespoke pieces from scratch — book a virtual or in-person appointment and we'll walk through diamond selection, setting design, metal, band width and finish. Turnaround on a bespoke 3 carat ring is typically 2–3 weeks. See our bespoke engagement rings and start-with-a-setting pages for the process.

Book a 1-on-1 Consultation with a Diamond Jewellery Expert in London

Prefer to see the diamonds in person? Our Mayfair showroom at 14 Hanover Square stocks hundreds of loose 3 carat and near-3 carat diamonds. Appointments are private, no-obligation, and typically last 45–60 minutes. We can also arrange virtual consultations with live diamond viewing on Zoom.

Frequently Asked Questions

How much does a 3 carat diamond ring cost?

A 3 carat lab-grown diamond ring starts from around £3,950 for a round D-VS1 in a plain solitaire setting. Natural 3 carat diamond rings start from around £18,500 for a G-SI1 round, with prices climbing for higher colour, better clarity and fancy shapes. The setting itself typically adds £700–£2,700 depending on metal, diamond count and complexity.

What are the dimensions of a 3 carat diamond in mm?

A round brilliant 3 carat diamond is approximately 9.3 mm in diameter. An oval 3 carat measures roughly 10.5×7.4 mm, a princess cut is about 7.6 mm square, an emerald cut is around 9.3×7 mm, a cushion 8.2×8.2 mm, and a pear or marquise around 11.5×7.6 mm. Fancy shapes appear larger than a round of the same weight.

How big does a 3 carat diamond look on the hand?

Reads immediately as "big" on any hand; Meghan Markle, Kim Kardashian and countless others wear rings in this weight range. On slimmer fingers it reads even larger; on wider fingers it stays balanced.

Should I choose lab-grown or natural for a 3 carat ring?

Lab-grown gives you the same look, sparkle and durability at 60–70% less — making a 3 carat achievable within a more everyday engagement-ring budget. Natural diamonds hold their story, rarity and long-term value, and remain the classic investment choice. Both come with full lab grading and lifetime service from us.

Which cut is most popular for a 3 carat engagement ring?

Round brilliant remains the most requested — it delivers the most fire and works with every setting style. Oval is the fastest-growing choice because it elongates the finger and appears larger than a round of the same weight. Elongated cushion and radiant are close behind for anyone wanting soft brilliance with a modern silhouette.

Do you ship 3 carat diamond rings internationally?

Yes — we ship fully insured, worldwide, at no charge. UK orders arrive next business day once the ring is finished. All ONLINE orders include a 30-day return window, a lifetime service warranty and a certified diamond grading report.

Can I customise a 3 carat setting?

Every 3 carat ring on our site can be customised: metal (18k white, yellow, rose gold or platinum), band width, claw count, hidden halo, finger size and finish. For a fully bespoke design, book a design consultation and we'll draw a CAD render before we make anything.

3 Carat Diamond Ring | Reve Diamonds