4 Carat Lab-Grown Diamonds
Rare, dramatic territory — about 10.2mm across in a round, a size lab grown finally makes attainable.
How big is a 4 carat lab grown diamond?
A 4 carat round measures roughly 10.2mm across — dramatic, rare territory that commands attention. In mined diamonds this size is the preserve of a few; lab grown opens it up to anyone who wants real presence on the hand.
How much does a 4 carat lab grown diamond cost?
A mined 4 carat is exceptionally expensive — its price reflects rarity as much as size. A lab grown 4 carat delivers the same dramatic look for a tiny fraction of that cost. Filter the live collection above to see real prices for your preferred cut, colour, and clarity.
Getting the most from 4 carats
- Cut first — at this size a precise cut is what keeps the stone brilliant rather than flat.
- Colour & clarity — bigger stones reveal more, so favour G+ colour and eye-clean clarity.
- Shape — elongated cuts spread the size even further across the finger.
Use the filters above to dial it in.
4 carat engagement rings
A 4 carat is a show-stopping centre stone. A secure, substantial setting and a slightly wider band balance and protect a diamond this size. Choose your loose stone here, then build it into the ring of your choice.
Why buy a 4 carat from Stienhardt
Every Stienhardt diamond is independently certified by IGI or GIA, graded for the full 4Cs, and conflict-free — all backed by free 30-day returns.
4 Carat Lab-Grown Diamonds — frequently asked questions
How big is a 4 carat lab grown diamond?
A 4 carat round is about 10.2mm across — dramatic, rare size with major presence on the hand.
How much is a 4 carat lab grown diamond?
A tiny fraction of a mined 4 carat, which is exceptionally expensive due to rarity. Filter the collection above to see live prices.
Why is a 4 carat so much cheaper lab grown?
A mined 4 carat is priced for rarity as well as size. Lab grown isn't supply-limited, so even this size stays attainable.
Does a 4 carat diamond look big?
Very — at about 10.2mm it's a show-stopper, and elongated shapes look larger still.
What colour and clarity should I choose for a 4 carat?
Larger stones reveal more, so favour G or better colour and eye-clean clarity for the best look.
Which shape looks biggest at 4 carats?
Elongated shapes — oval, marquise, emerald, pear — wear the largest at this size.
Are 4 carat lab grown diamonds real diamonds?
Yes — they're real diamonds, chemically and optically identical to mined stones, and recognized as diamonds by the FTC.
Are 4 carat lab grown diamonds certified?
Yes. Every Stienhardt diamond is independently certified by IGI or GIA and graded for the full 4Cs.
Can I set a 4 carat into an engagement ring?
Absolutely. Choose your loose stone, then pick a setting and we'll mount it for you.
What is your return policy?
Free 30-day returns on diamonds and jewelry.