What a lab-grown diamond actually is
A lab-grown diamond is diamond. It is made of carbon atoms arranged in the same cubic crystal structure as a diamond formed in the earth, so it has the same hardness, the same refractive index and the same way of returning light to the eye. The difference is where and how it grew: above ground, in a controlled chamber, over weeks rather than over geological time.
There are two main growing methods. HPHT (high pressure, high temperature) recreates the crushing pressure and heat found deep in the earth. CVD (chemical vapour deposition) builds a crystal layer by layer from a carbon-rich gas. Both methods can produce excellent stones, and both can produce poor ones. The method matters far less than the finished stone's cut, colour and clarity, which is why we always talk about the individual diamond rather than the process behind it.
It is worth being clear about what a lab-grown diamond is not. It is not a simulant. Cubic zirconia and moissanite are different materials with different optical properties. A lab-grown diamond tests as diamond on standard diamond testers, because it is diamond.
Why couples choose lab-grown for an engagement ring
People come to lab-grown for different reasons, and none of them is the "right" one:
- Budget allocation. For a given budget, lab-grown usually allows a larger or better-cut centre stone than a mined diamond of similar grade. Many couples use that room to choose a finer cut or a better setting instead of simply going bigger.
- Known origin. A lab-grown stone has a traceable production story from the start.
- Design freedom. Because the stone is less of the budget, there is more room for the part that makes a ring personal: the setting, the proportions and the details only the wearer will notice.
We would add one honest caveat. Lab-grown diamonds are bought for love and for wearing, not as a financial investment. Resale prices for lab-grown diamonds are low and uncertain. If resale value matters to you, take that into account.
How a lab-grown diamond is graded
Lab-grown diamonds are graded on the same "4Cs" as mined diamonds:
- Cut. This is how well the stone is proportioned and polished to return light. For round brilliants, cut grade is the single biggest factor in how lively a diamond looks.
- Colour. This measures how colourless the stone is, on a scale from D (colourless) downward. Many people find stones in the near-colourless range look white once set, especially in yellow or rose gold.
- Clarity. This covers the presence of internal or surface characteristics. "Eye-clean" — nothing visible without magnification at a normal viewing distance — is a sensible target for most rings.
- Carat. This is weight, not size. One carat equals 0.2 grams. Two stones of the same carat weight can look different sizes depending on cut and shape. Our guide to carat versus millimetres explains this in detail.
Independent laboratories such as IGI grade lab-grown diamonds and issue a report that identifies the stone as laboratory-grown. Where a report applies to your stone, we share it before you approve the design. Our article on reading a lab-grown diamond report walks through each line.
Choosing a shape
Shape is the most personal decision and the one that most changes the look of the ring.
- Round brilliant is the most fiery shape, timeless and forgiving.
- Oval gives an elongated outline that can make fingers look longer, and it usually faces up larger than a round stone of the same weight.
- Emerald cut has long, mirror-like step facets. It is calm and architectural, and it rewards high clarity.
If you are torn between two shapes, our comparison of emerald and oval ring designs is a good next read. You can also browse stones directly in the Diamond Library.
Choosing a setting
The setting holds the stone and defines the silhouette:
- Solitaire: one stone, nothing to distract from it.
- Halo: a ring of small diamonds around the centre stone, for extra sparkle and a larger face-up look.
- Hidden halo: small diamonds set under the centre stone, visible from the side.
- Pavé band: small diamonds set along the band.
- Three stone: a centre stone flanked by two side stones.
Prongs and bezels each have strengths. Our bezel vs prong guide covers security, light and maintenance. You can see our current outlines in the Setting Gallery.
Choosing a metal
We work in 18k white, yellow and rose gold. White gold makes a stone look icy and modern. Yellow gold reads warm and classic, and it can make a near-colourless stone look whiter by contrast. Rose gold is soft and romantic. All three are durable for daily wear. White gold is usually rhodium-plated and may need re-plating over time to keep its bright white finish.
How a custom lab-grown ring is made with us
A custom ring should never be a surprise to the person paying for it. Our process has two approval points before anything is made:
- Brief and quote. You tell us about the person, the shape, the budget and the feeling you want. We confirm the stone options and the price.
- Deposit. A 75% deposit confirms the commission and reserves the stone.
- Line sketch. A hand-drawn line sketch shows the outline, proportions and details. You can ask for changes at this stage.
- CAD confirmation. Once the sketch is approved, we prepare a CAD model with accurate measurements, built around the actual dimensions of your stone. Nothing goes into production until you approve the CAD.
- Production and balance. The remaining balance is due after CAD approval, and then the ring is made.
If you cancel before production starts, the deposit is refundable. Because every ring is made for one person, we do not accept returns once a ring has been produced. We are explaining that now, not in small print. One size change is free (you cover shipping). A change of up to 2 Hong Kong sizes is possible but requires a new band, charged separately; your centre diamond is reused. The full details are in our Custom Order Terms.
A short checklist before you start
- Know the ring size, or plan how you will find it. Our ring size guide can help.
- Choose a shape first and a setting second.
- Decide which matters more: face-up size or cut quality.
- Ask for the grading report when one applies.
- Read the terms before you pay a deposit.
For a fuller list of what to ask, see our custom ring quote checklist.
Where to begin
If you already know the look you want, start with a setting. If the stone comes first, start with a diamond. Either way, you will see a line sketch and then a CAD before anything is made, so there is time to get it exactly right.
Questions to ask about the individual stone
A grading report tells you a great deal, but not everything. When you are choosing a centre stone, ask the jeweller these questions:
- Can I see a photo or video of this exact stone? Two stones with identical grades can look different, especially in how evenly they return light.
- Where are the inclusions? An inclusion near the edge, which a claw may cover, matters less than one in the middle of the table.
- What are the measurements? For an oval or emerald cut, the length and width tell you the outline. For a round, the diameter tells you the face-up size better than the carat weight does.
- Has the stone been treated after growth? Some lab-grown diamonds receive treatment to improve colour. A reputable report notes this where it is detected.
- Is fluorescence present? In most stones it has no visible effect, but it is worth knowing.
We answer these questions for every stone we propose, because the CAD for your ring is built around that specific stone.
Matching the stone to the setting
The stone and the setting should be chosen as a pair:
- A halo surrounds the centre stone with bright accents. That can make a slightly warmer stone look whiter, so it can be a sensible place to choose a little lower on colour.
- A solitaire shows the stone alone. Cut quality matters most here, because nothing else adds sparkle.
- Yellow and rose gold reflect warm tones into the stone, which hides a little warmth. White gold shows the stone's own colour more truthfully.
- A bezel covers the outline slightly, so a stone in a bezel faces up a little smaller than the same stone held in claws.
Caring for a lab-grown diamond ring
Care is the same as for any diamond ring. Clean it gently with warm water, mild soap and a soft brush, paying attention to the underside of the stone, where lotion collects and dulls the sparkle. Take the ring off for heavy work, the gym and household chemicals. Have the claws checked by a jeweller from time to time, especially on pavé and halo designs.