Large carat laboratory-grown diamonds

Large carat lab-grown diamonds for the trade

Centre stones and statement sizes, as single stones or matched pairs, with independent grading reports.

Send a requirement Request stock list

What matters more at large sizes

  • Colour consistency. Large stones show body colour more; specify the colour range and whether as-grown or treated is acceptable.
  • Strain and graining. Growth features can be more visible in bigger stones. We inspect rough before planning and will show you video of the finished stone.
  • Make. On a large stone, cut quality decides how big it looks and how it performs. Tell us your proportion preferences.
  • Report. We recommend an independent report on every large stone. Check it with our certificate checker.

Shapes for centre stones

Round, oval, emerald, cushion, pear, radiant, marquise, asscher and heart. Elongated shapes such as oval, pear and marquise face up larger for their weight.

Matched pairs

For earrings and three-stone designs we match pairs on size, shape outline, colour and clarity. Tell us your tolerance.

Send us your requirement

Use the requirement form or email [email protected] with:

  • Shape: round, oval, emerald, cushion, pear, radiant, princess, marquise, asscher, heart or others
  • Carat range per stone, or total carats for a parcel
  • Colour and clarity range
  • Quantity, and whether you need matched pairs or calibrated sizes
  • Grading reports, if you need them, and which laboratory
  • Delivery country and the date you need the goods

We reply with what we have in stock and what we can grow for you.

Questions buyers ask

What should I check on a large lab-grown diamond?

Look at the grading report for growth method and any post-growth treatment, then check colour consistency, strain or graining visible under magnification, and how the stone faces up for its weight. Ask us for video of the actual stone.

How do I check a grading report?

Use our certificate checker, which opens the laboratory's own report-check page for the number you enter. Compare the measurements, carat weight and laser inscription with the stone you receive.

Can you make matched pairs and calibrated parcels?

Yes. Tell us the shape, size tolerance and quantity, and we will quote from stock or plan a production run.