A no-nonsense guide to lab grown diamond engagement rings - from someone who actually wants to help you get it right.

Here's the thing about buying an engagement ring: there's a lot of noise out there. Jewellers who want you to spend more than you need to. Outdated rules about how many months' salary it should cost. And a whole lot of mystique around diamonds that honestly doesn't need to exist. You don’t need to become a diamond expert. You just need to know what actually matters.

So let's cut through it.

This is the guide we wish existed when we were figuring all of this out - straightforward, honest, and actually useful.

First things first: are lab grown diamonds real diamonds?

Yes. Full stop.

A lab grown diamond is not cubic zirconia. It's not moissanite. It's not a "diamond simulant." It is a diamond - same carbon structure, same hardness, same optical properties, same everything. The only difference is that it was grown in a laboratory rather than pulled out of the ground over billions of years.

Even gemologists can't tell the difference with standard tools. Specialised equipment can - because lab grown diamonds are often too perfect to be natural, which is honestly a bit funny when you think about it.

Every diamond in the THERESHEIS.jewels engagement ring collection is IGI certified. That means an independent gemological institute has graded it and given you a document saying exactly what you have. No guesswork.

Why lab grown, though?

Two reasons, mainly.

The value is genuinely extraordinary. A lab grown diamond costs around 60–80% less than a mined diamond of equivalent quality. That means a stone that would cost £8,000 mined might cost £1,800 lab grown - same colour, same clarity, same certificate, same ring on your finger.

The ethics are cleaner. For many people, lab grown feels like the cleaner, more considered choice: no traditional diamond mining, no conflict diamond concerns, and far less of the uncertainty that can come with mined stones.

The cuts we carry - and what they actually mean for you

Oval cut

Right now, oval is the cut. And there's a reason for it - it's genuinely flattering on almost every hand shape. The elongated form makes fingers look longer, and because of the way it's faceted, it tends to look larger than a round diamond of the same carat weight. You're getting more visual impact for your money.

Our oval cut rings come in 1ct, 2ct, 3ct and 4ct, in 18ct yellow gold or 18ct white gold, from £1,850. If you're not sure where to start, start here.

Emerald cut

This one is for the woman who doesn't need to shout. The emerald cut has long, rectangular facets that create this incredible depth - less sparkle, more of a mirror-like shimmer. It's architectural and sophisticated and a little bit intimidating in the best way.

We carry emerald cut rings in 2ct, 3ct and 5ct in 18ct white gold, from £2,495. The white gold really does suit this cut — the clean lines of the stone and the cool metal feel made for each other.

Radiant cut

Think emerald shape but with brilliant-cut facets underneath - so you get that modern rectangular silhouette but with serious sparkle. It's a bit of a best-of-both-worlds cut, and it looks stunning in yellow gold.

We have one radiant cut ring: 3ct, 18ct yellow gold, £2,950.

Carat: what size actually looks like in real life

Carat is weight, not size - but weight and size are related, so here's a rough guide for oval cuts specifically:

• 1ct - classic, wearable every day, genuinely beautiful. Not "small."
• 2ct - you notice it immediately. A proper presence on the hand.
• 3ct - bold. This is a statement piece.
• 4ct–5ct - nobody is missing this ring.

Hand size matters here. On slender fingers, a 2ct oval can look like a 3ct on broader hands. If you're unsure, it's worth looking at reference photos online of real hands wearing different carat weights - it's the best way to calibrate your expectations.

Yellow gold or white gold?

All our rings are 18ct solid gold - the finest standard for fine jewellery, not plated, not hollow.

Yellow gold is warm, timeless, and genuinely beautiful against every skin tone. It has a richness that white metals can't replicate. And for a D/E colourless diamond? The contrast between a cool white stone and a warm gold setting is something special.

White gold has a cool, platinum-like finish. It's more contemporary, and it suits people who wear predominantly silver-toned jewellery. It enhances the whiteness and brilliance of the diamond - if you want the stone to look as bright as possible, white gold does that. Worth knowing: white gold is rhodium plated and may need replating every few years to maintain its colour. It's a simple, inexpensive process.

What does IGI certified actually mean?

IGI is the International Gemological Institute - one of the most respected independent diamond grading organisations in the world. When a diamond is IGI certified, it means a third party (not the jeweller selling it to you) has assessed the stone and produced a report documenting:

• Carat weight
• Cut grade
• Colour grade (ours are D or E - colourless)
• Clarity grade (ours are VS - inclusions invisible to the naked eye)
• Confirmation it's a lab grown diamond
• A unique report number you can verify online

You get this certificate with your ring. Keep it - you'll need it for insurance.

How much should you actually spend?

The "three months' salary" rule was invented by De Beers in the 1930s to sell more diamonds. It is not a real rule. Spend what you're comfortable with.

Our rings start at £1,850 for a 1ct oval in 18ct gold with an IGI certified diamond. For the equivalent mined stone at the same quality, you'd be looking at significantly more. That's the honest answer.

A few practical things

Our rings are made to order. When you buy, your ring is made specifically for you. This is how we keep quality high and prices honest. If you have a deadline - a proposal date, an anniversary - get in touch before you order so we can confirm timing.

Complimentary UK delivery is included on everything.

Klarna is available if you want to spread the cost. Check eligibility at checkout.

Questions? Email us at hi@theresheisjewels.com. We're real people and we actually reply.

The collection

Browse all engagement rings →

All rings: 18ct solid gold. IGI certified lab grown diamonds. D/E colour. VS clarity.

THERESHEIS.jewels is a solid gold jewellery brand based in Edinburgh. For women who know their worth.