Independently certified · Johannesburg

Lab Grown Diamond Engagement Rings

A real diamond — same fire, same hardness, same forever — for a fraction of the price of mined. Made, sized and backed in our own Johannesburg workshop.

  • Certificate with every stone
  • Made in our own workshop
  • Payflex available
A certified lab grown diamond engagement ring made by Cassims & Co. in Johannesburg
4.8 ★377 Google reviews
CertifiedCut, colour, clarity & carat in writing
In-houseMade, sized and repaired by us
PayflexInterest-free instalments
A certified lab grown diamond ring photographed at Cassims & Co.

Yes — it is a real diamond

A lab grown diamond is carbon crystallised under the same heat and pressure that forms a diamond underground, recreated above ground. It is not a simulant or a substitute. Its chemistry, its hardness and the way it bends light are identical — which is why a jeweller's diamond tester reads it as a diamond, because it is one.

The only meaningful difference is where it formed, and what it costs. Because no mining is involved, every stone is also guaranteed conflict-free.

  • Hardness 10 — the hardest material there is, same as mined
  • Will not cloud, fade or dull with wear
  • Independently certified and graded, in writing

Lab grown, natural or moissanite

The honest comparison. Choosing well starts with straight answers, not sales talk.

Natural diamond

Tradition & rarity
  • Is it a diamondYes
  • Hardness10 — hardest known
  • SparkleClassic diamond brilliance
  • Reads as diamondYes
  • Cost for the lookThe premium option

Lab grown diamond

Most diamond per rand
  • Is it a diamondYes — chemically identical
  • Hardness10 — hardest known
  • SparkleClassic diamond brilliance
  • Reads as diamondYes
  • Cost for the lookA fraction of mined

Moissanite

Everyday affordability
  • Is it a diamondNo — silicon carbide
  • Hardness9.25 — very durable
  • SparkleMore rainbow fire
  • Reads as diamondNo
  • Cost for the lookThe budget option

Not sure which is right for you? Come in and look at all three side by side on your own hand, under the same light. Most people find the price difference more surprising than the sparkle difference. Ask us anything on WhatsApp first if you'd rather.

Six styles, in the boutique today

A solitaire is where most people start — but it is not where most people finish. Prices and availability read live from our shelves.

What the step up actually looks like

Two real rings from our cabinet. Same 9ct yellow gold, same round brilliant cut, same bench. Only the stone changes.

That gap is the whole argument for lab grown. With a mined stone, the same step up costs multiples of this. Here it buys you the carat weight you actually wanted, without giving up cut, colour or clarity.

Reading your certificate — the 4Cs

Every stone we sell is graded on four qualities. Here's what they mean in plain language.

The four qualities graded on every diamond certificate — cut, colour, clarity and carat
Cut

How it sparkles

How well the stone is shaped and faceted. The single biggest factor in brilliance — and where craftsmanship shows.

Colour

How white it is

Graded from D downwards. The difference is real, but subtler to the eye than most people expect.

Clarity

How clean it is

How free the stone is of tiny internal marks. Most are invisible without magnification.

Carat

How big it is

The weight. This is where lab grown wins — more carat for your budget, without compromising the other three.

Inside the Cassims & Co. boutique at Mall of the South, Johannesburg

Come and look at all three

A photograph cannot settle this. Lab grown, natural and moissanite look different in the hand to how they look on a screen, and the only honest way to choose is to see them together under the same light.

Bring the budget you have in mind. We'll lay out what it buys in each, and tell you plainly which we'd choose and why. No appointment, no pressure.

Why buy it from us

We are a family jewellery business with our own workshop. That changes what we can do for you.

Compare before you commit

See lab grown, natural and moissanite together, on your hand, under the same light.

Made and backed in-house

Your ring is sized, set, engraved and cared for by the people who made it — not sent away. Workmanship guaranteed.

Pay over time

Payflex at checkout splits the cost into interest-free instalments. Take the ring home now, spread the payments.

Sourced to your brief

Our suppliers carry far more than fits in a cabinet. Name a carat, shape and budget and we'll find the stone.

Aftercare for life

Cleaning, polishing, resizing and repairs in our own workshop, for as long as you own the piece.

Insured delivery

Fully insured delivery anywhere in South Africa, properly packaged — or collect in person in Johannesburg.

How it works

From first look to the ring on the hand.

A Cassims & Co. jeweller sizing a ring at the bench in the Johannesburg workshop

Nothing leaves the building

Sizing, setting and engraving all happen at our own bench. That means days rather than weeks, and the person who adjusts your ring is the person who made it.

It also means we can build around a stone, rather than only selling what is already set.

Browse or visit

See the collection online, or come and look at the stones in person at Mall of the South.

Choose stone and setting

Take a ready-made piece, or design around a certified stone that fits your budget — including carats we don't have on the shelf.

Sized and finished here

Our workshop sizes, engraves and finishes your ring properly, by hand.

Looked after for life

Leave with your certificate, and bring the ring back any time for cleaning, polishing or resizing.

Rated 4.8 ★ from 377 Google reviews

In our customers' words

Our reputation is the whole business. These are real reviews on Google, where we can't edit a word.

★★★★★

“Ordered a custom ring, the whole process was simple and the services was fantastic. Very helpful from the onset, the ring turned out perfect. I would definitely recommend them!”

Dominique Caldora
★★★★★

“Really loved the service and quick turnaround. Communication was also fast and Nazia was a great help. Thank you”

Tatiana Kalambaie
★★★★★

“The people who worked there are so helpful. I bought a tungsten ring from them today and had it engraved. It looks absolutely phenomenal”

Nichelle Diedericks
★★★★★

“Exceptional service and delivery!!! Received my online order in less than 24 hours and was kept updated of progress of delivery throughout. And the item purchased is simply one of a kind.”

Merissa Govender

Two ways to get the ring you want

Take one that exists, or have one made. Both start with a conversation.

Choose from stock

Everything in the cabinet is certified, sized in-house and ready to wear. Most rings are finished and in your hands within 24 hours.

Have it made for her

A specific carat, a shape we don't stock, a setting from a photograph, or a stone reset from a ring you already own. We make it at our own bench, with the same certification and guarantee.

Prefer to just send us the details? Use the contact form and we'll come back to you with options and a price.

Questions we get asked

Will anyone be able to tell it's lab grown?

No. Not by eye, not through a loupe, and not with a standard diamond tester. Telling a lab grown diamond from a mined one requires specialised laboratory equipment — which is exactly why certification matters, and why every stone we sell comes with one.

Do lab grown diamonds fade or lose their sparkle?

No. It's a diamond, so it doesn't cloud, fade or wear down. It will look the same in fifty years as it does today, with the same simple care any diamond needs.

Is moissanite the same thing?

No — moissanite is a different stone entirely. It's beautiful and hard-wearing, but it isn't a diamond, and it throws more rainbow fire than white light. It's the right answer for some budgets and we stock a full moissanite range. If you want a real diamond at the best possible price, lab grown is the answer.

What if the carat, shape or ring size I want isn't in stock?

What's online is what's ready today, and it's only a part of what our suppliers carry. If you're after a particular size — a 3ct round, say — or a shape, colour grade or ring size we don't have, tell us. We'll source the stone and make the setting around it, with no premium for going bigger. Message us on WhatsApp, send us the details, or come in.

Can I pay it off over time?

Yes. Payflex at checkout splits your purchase into interest-free instalments, so you take the ring home now and spread the cost. Ask in store, or select Payflex when you check out online.

What if the ring doesn't fit?

We resize it in our own workshop at Mall of the South — not sent away to a third party. Because we manufacture in-house, adjustments are quick and done properly.

Are lab grown diamonds a good investment?

We'll be straight with you: no diamond, mined or lab grown, should be bought as a financial investment. You buy a diamond to wear it and for what it means. Lab grown simply means spending less for more of what you actually see on the hand.

Can I see them in person first?

Please do. Visit us at Shop G098, Mall of the South, Johannesburg. Bring your budget and we'll show you exactly what it buys across lab grown, natural and moissanite, side by side. No pressure and no sales talk. Directions and opening hours.

Tell us your budget. We'll show you what it buys.

Message us with what you have in mind — a carat, a shape, a number — and we'll come back with honest options, including ones that aren't on the website. Or walk in and see them for yourself.