How to Choose Your Own Lab-Grown Diamond for a Custom Engagement Ring

Choose the shape and setting style first, then compare stones by their measurements, video and grading report rather than by carat weight alone. Check that the report can be verified online, that the cut or outline suits the setting, and that your jeweller will make the setting to that stone's exact measurements.

1. Pick the shape and setting style. The setting decides what size and outline of stone works, and how much of the budget is left for the diamond.
2. Set colour and clarity limits. For most lab-grown diamonds, D to F colour and VS1 clarity or better look colourless and clean to the eye.
3. Compare millimetres, not just carats. Face-up size is what people see on the hand.
4. Check the cut or the ratio. Rounds have a cut grade. Other shapes are judged on their outline and a video.
5. Watch a video of the actual stone. It shows what the report cannot, such as dark areas or a bow tie.
6. Verify the report. Look up the report number with the lab and match it to the inscription on the stone.

Choose the shape first, then the setting, then the diamond. Most custom rings are made around the stone, so the setting's claws or bezel are sized to the diamond's measurements, but the design you want limits which stones suit it. A bezel or east-west setting, a toi et moi with two stones, or a large stone in a thin band all narrow the choice.

The setting also takes a real share of the budget. In a simple 14k gold four-claw solitaire with us, the setting is $1,260, while the median round lab-grown diamond of 1.00 to 1.09 carats on our feed is $1,242. Knowing the setting cost first tells you what is left for the stone.

IGI says its lab-grown diamond reports can note the growth process and the presence of treatments in the comments section. Our guide to IGI vs GIA reports explains how to read and verify each one.

Because carat is weight, not size. A stone cut deep carries more of its weight below the surface, so it looks smaller from above. These are the 527 stones between 1.00 and 1.09 carats on our live feed of 5,265 lab-grown diamonds on 17 September 2026:

At the same weight, the longest oval was 1.1mm longer than the shortest, and the longest pear was 2.0mm longer. Ask for the measurements of every stone you are considering, and compare them to the setting you have chosen.

It depends on the look you want. A higher ratio gives a longer, slimmer stone, and a lower one gives a shorter, wider stone. The ratio is length divided by width, and most stones on our feed sit in these ranges:

Cushions vary the most because they are cut both square and elongated. If you are choosing an elongated cushion, set a minimum ratio so square stones are left out. Our oval cut buying guide covers ratio and the bow tie in more detail.

For round brilliants, yes. GIA's cut scale applies to standard round brilliants in the D to Z colour range, and cut is what gives a round stone its brightness and sparkle. On our feed, 522 of the 704 round stones were graded Ideal and 182 Excellent by IGI.

Other shapes usually have no cut grade. Only 3 of the 4,561 fancy-shaped stones on our feed carried one. For ovals, pears, marquises, emeralds, radiants, cushions and princesses, judge the cut from a video: look for even sparkle across the stone, and for a dark bow tie across the middle of an oval, pear or marquise that stays visible as the stone moves.

Yes, some jewellers will set a stone you bought elsewhere, but the terms vary and it does not always save money. Before you buy a loose stone, ask the jeweller who will make the ring:

• Who is liable if the stone is damaged. Unique Diamonds' terms say it accepts no liability for breakage that may occur while setting, removing, resizing or repairing a supplied stone.
• Whether the stone must be insured and certified. Kate & Kole requires supplied stones to be insured and certified, and says it charges a markup comparable to sourcing the stone itself, so supplying your own diamond typically does not reduce the cost.
• Whether the stone suits the design. The jeweller needs the exact measurements before modelling the setting.
• What the warranty covers. A warranty on the ring may not extend to a stone the jeweller did not supply.

Buying the stone and the setting from the same jeweller keeps the responsibility for both in one place.

You choose your stone in the same place you design your ring. You start with the setting, choose the metal, band and ring size, and then pick your diamond from the 5,265 IGI-certified lab-grown stones we source, all D to F colour and VS1 clarity or better.

• Filter by what matters to you: carat weight, colour, clarity, and length to width ratio on elongated shapes.
• See the stone move. Most stones have a 360 degree video you can rotate before you choose.
• Read the report. Each stone's IGI certificate opens from its details, so you can check the grades and report number.
• Save stones to compare. Favourites keep the stones you like, with today's price.

Already bought a lab-grown diamond elsewhere? We will set a stone you bought from another seller too. Get in touch with its grading report, and we will talk you through the design around it.

If you would rather talk it through, you can book an appointment or ask us anything, and Brie will help you compare the stones you are considering.

Can I see the diamond before it is set?

Online, you see the stone's video and grading report before you buy. Ask for the video of that exact stone rather than a sample, and check the report number with the lab.

Is it cheaper to buy a loose lab-grown diamond and a setting separately?

Not always. Some jewellers add a markup or a setting fee for supplied stones, and you may carry the risk if the stone is damaged. Compare the complete price, including setting, insurance and warranty.

What carat size should I choose?

Choose by millimetres on the hand, not the carat label. A round lab-grown diamond of about 1 carat on our feed measured 6.32 to 6.73mm across. Our 1 carat price chart shows what each shape costs at that size.

What colour and clarity should I choose for a lab-grown diamond?

D to F colour and VVS2 or VS1 clarity suit most rings. Our guide to the best colour and clarity for a lab-grown diamond shows what each grade costs.

Thanks for reading, Jared and Brie