Between the jargon (what even are the 4Cs?), the specs, certification, and dozens of retailers all claiming to offer the best deal, buying a diamond can feel like a lot.
This guide covers what actually matters, what you can safely skip, and how to make a decision you're happy with.
In this guide
Set a budget you're comfortable with
Pick a number that works for you, then treat it as your limit.
It's easy to get nudged into "just one more step up". A slightly higher colour, a slightly higher clarity, a slightly bigger carat. In practice, many of these small upgrades are hard to notice once the diamond is set and viewed at a normal distance.
If you'd rather keep your spend steady, or put the difference towards a setting you love, that's a perfectly good call.
A good starting point for specs
With lab-grown diamonds, the price gap between very similar stones is often small. You can check current averages on our price table, or see how pricing has shifted over time on our price history chart.
Here's where we'd typically start:
- Cut: Ideal - do not compromise here. Cut is what gives a diamond its light and sparkle. (only round diamonds are graded on cut)
- Clarity: VVS2 or better - meaning any inclusions are tiny and invisible to the naked eye. Flawless diamonds are beautiful but do you carry around a microscope?
- Colour: H or better - colour grades run D (completely colourless) down to Z. If your budget allows, F or E, but you pay a huge premium for D diamonds.
- Finish: Polish and Symmetry to Excellent - there's no reason to settle for less.
- Fluorescence: None - same as above, there's no reason to settle here.
Cut grading is standardised for round diamonds. For other shapes, you'll sometimes see retailer cut ratings, but they're not applied consistently and I feel for the most part they are misleading. If it's not on the certificate, don't pay it much mind.
After that, I start to play with carat to figure out what size makes sense. Lab diamonds aren't priced like mined diamonds, so you don't necessarily have to break the bank to go bigger, but for practical reasons it's worth keeping size in mind too. Very large stones can catch on clothes and get in the way day-to-day.
Here's a ready-made search link with my starting filters applied: start with these filters.
Shop Around and Compare
A lot of retailers list diamonds from the same virtual inventory. So they're listing the same stock from multiple sources even though they don't physically have the diamond themselves. If you order it, they order it. That means you can genuinely see the exact same stone on multiple sites, sometimes with wildly different pricing and some of the diamond details obscured.
When you compare diamonds, make sure you're comparing like-for-like:
- Same stone (use the certificate number to confirm)
- Same grading lab (IGI vs GIA vs others)
- Same key specs (carat, colour, clarity, cut, measurements)
A quick note on carat:
People often search around neat milestones. In practice, stones sitting just below popular thresholds (0.98 rather than 1.00, or 1.47 rather than 1.50, for example) can look extremely similar once set. That can give you more flexibility elsewhere (like cut quality, shape choice, or overall budget).
If a listing makes it strangely hard to identify the exact stone, that's usually not an accident. The site is probably trying to stop you from comparing it easily elsewhere, which means less pricing pressure.
Always Look for a Certificate Number
Can't see a certificate number? You're probably paying too much.
A grading report is your anchor. It confirms the diamond has been independently assessed, and it gives you a unique certificate number you can reference when you compare options.
If a retailer hides the certificate number, it's usually for one reason: it makes the diamond harder to compare elsewhere. Less comparability means more pricing power.
A proper report includes the 4Cs, measurements, and notes about characteristics. With the certificate number visible, you can check you're comparing the same stone and the same grading standard, not just similar-looking specs.
We exclusively sell IGI-certified lab-grown diamonds. Every diamond on our site includes its certificate number and report details, because that's what makes fair comparison possible.
Don't Decide Without Seeing the Diamond in Motion
A certificate tells you what a diamond is. A video shows you how it behaves.
Video lets you check things that matter in real life:
- How the diamond handles light (brightness, patterning, sparkle)
- Whether anything stands out to your eye
- The overall "personality" of the stone
Every diamond on our site includes a video. If there isn't one for a particular diamond you're considering, email us at hello@diamond-labs.co.uk and we'll do our best to source one.
Choose a Seller With a Straightforward Returns Policy
Even when you've done all the sensible checks, a diamond is still a visual choice. A clear returns policy takes the pressure off and lets you decide with confidence.
At Diamond Labs, we offer a 30-day return window. If it's not right once you've had a proper look, you can return it.
Don't Forget the Costs Beyond the Diamond
A loose diamond is only one part of the full picture. If you're planning a ring, it's worth keeping space in your overall budget for:
- The settingMetal choice, design complexity, side stones
- Jeweller feesSetting the stone, resizing, finishing
- Insurance and maintenanceCover, periodic checks and cleaning
One advantage of buying a loose diamond is flexibility. You can choose the diamond first, then work with a local jeweller on a setting that fits your style and budget.
It's also worth understanding how diamonds hold their value over time, even if you're not planning to sell. We've put together a breakdown of lab diamond resale value with worked examples comparing the real losses on lab-grown and mined diamonds.
A Quick Note on Who We Are
Diamond Labs is a UK-based store for loose, IGI-certified lab-grown diamonds.
I got into this business after shopping for a diamond for my wife, I stumbled across something that surprised me: the same diamonds appearing across many websites at wildly different prices. And if you're buying in the UK, there's another layer of stress on top. The worry that a "good price" might turn into something else once you factor in import VAT, shipping, tariffs, insurance, or unexpected fees.
That was exactly what I worried about when I was buying, and it's what I wanted to make go away for other people.
So we keep it simple:
- Loose diamonds
- Clear videos
- Straightforward pricing (no surprise import fees or shipping costs)
- A 30-day return window
We hope this guide has helped you feel more confident about buying a lab-grown diamond.
If we can help in any way, you can reach us at hello@diamond-labs.co.uk