A clarity enhanced diamond is a real diamond that has been treated to make its inclusions less visible. The stone is genuine; the clarity you see is not entirely natural. The treatment is done after the diamond is cut, and it is meant to make a lower-clarity stone look better than its grade would suggest.

This is a subject where a jeweller should be blunt with you rather than diplomatic. There are things you need to know before buying one, and we will say up front that we do not sell clarity enhanced diamonds. Every centre stone we set is an untreated lab-grown diamond with a free IGI certificate. What follows is the honest explanation so you can judge for yourself.

The two treatments you will encounter

Treatment	What it does	Permanent?	Detectable?
Fracture filling	A glass-like substance is forced into surface-reaching fractures, so they stop reflecting light and become far less visible	No — can be damaged by heat and some chemicals	Yes, by a trained gemmologist under magnification
Laser drilling	A microscopic tunnel is burned to a dark inclusion, which is then bleached or dissolved so it no longer reads as a black speck	Yes — stable and permanent	Yes; the drill hole itself is visible under magnification

Both start with a diamond that would grade poorly — typically I1 to I3, the bottom of the clarity scale. The treatment improves the appearance, not the underlying stone.

How fracture filling works

A feather is a small internal fracture in a diamond. It shows because there is a gap between two surfaces inside the stone, and light bounces off that gap, making it flash white or silvery.

Fracture filling injects a molten glass-like material into fractures that reach the surface. The filler bends light at almost the same rate as diamond does, so the fracture stops reflecting and effectively disappears from view. A stone that looked visibly cracked can look clean.

The important word is “almost”. The match is close, not perfect, which is why treated stones can show a distinctive effect known as a flash effect — a flash of orange, purple, pink or blue along the filled fracture when you tilt the stone under magnification. That is how a gemmologist identifies the treatment.

The problem with fracture filling

It is not permanent, and that has real consequences for anyone who owns the ring.

• Heat can damage it. The jeweller’s torch used for resizing, retipping claws or any ordinary repair can cloud, discolour or drive out the filler. The stone must be removed from the setting first, and the jeweller must be told the diamond is filled.
• Some cleaning methods can affect it. Ultrasonic and steam cleaners, along with strong acids, can be a risk. Routine professional cleaning becomes something you have to warn people about.
• It can degrade over time. Fillers can discolour with age and exposure, meaning the fracture becomes visible again years later.
• It usually needs re-treating. If the filling is damaged, the stone can be filled again — but that is another cost, and it tells you what you actually own.

There is also a documentation problem. Some major laboratories decline to issue a full grading report for a fracture-filled diamond, on the grounds that the clarity grade would not reflect a permanent characteristic of the stone. They will identify the treatment on an identification report instead. That should tell you how the trade views it.

Laser drilling is a different matter

Laser drilling is permanent and stable. A microscopically fine channel is burned from the surface to a dark inclusion, and the inclusion is then bleached or dissolved so it no longer looks like a black dot.

The drill hole remains — it is visible under magnification as a fine line or a tiny surface opening — but it does not degrade, it survives heat and cleaning, and it does not need maintaining. Laboratories do grade laser-drilled diamonds, with the treatment disclosed on the report.

So of the two, laser drilling is far less problematic. It still means you are buying a stone that began at the bottom of the clarity scale.

Disclosure: what you are entitled to know

Any treatment that affects a diamond’s appearance must be disclosed at the point of sale. That is standard practice throughout the trade, and a seller who does not volunteer it is not doing their job.

Ask these questions directly:

• Has this diamond been treated in any way?
• Is it fracture filled, laser drilled, or both?
• Is there a laboratory report, and does it state the treatment?
• What care instructions does the treatment require?
• Will the treatment be noted on my valuation for insurance?

If the answers are vague, walk away. A treated stone is not a scandal; an undisclosed one is.

What clarity enhancement does to value

It lowers it, substantially. A clarity enhanced diamond is worth considerably less than an untreated stone of the equivalent apparent clarity, because the market prices it against its original grade rather than its treated appearance.

Resale is harder too. Many buyers and dealers will not touch fracture-filled stones at all, and insurance valuations should record the treatment, which affects any replacement settlement.

We are not going to quote figures for the discount, because reliable published numbers do not exist and any range you see online is usually somebody’s guess. What is safe to say is that the price advantage on the shelf reflects a real reduction in what you own.

The honest alternative

Clarity enhancement exists to solve a problem: people want a large, clean-looking diamond for a modest budget. That is a completely reasonable thing to want.

Lab-grown diamonds solve the same problem without a treatment. Because growth conditions are controlled rather than geological, higher clarity grades are produced far more consistently than they are found in the ground. A VS or even VVS grade in a decent size is genuinely reachable — no filler, no drill hole, nothing to declare to a jeweller before a repair, and a normal certificate.

That is why every centre stone we set is untreated and IGI certified. Some examples, all lab-grown and all with certificates:

• Our Stackable Pear Cut Engagement Ring, £503 correct at the time of writing.
• Our Solitaire Dutch Marquise Cut Engagement Ring, £932 correct at the time of writing.
• Our Bezel Lozenge Cut Engagement Ring in Yellow Gold, £939 correct at the time of writing.

You can browse everything in engagement rings, or filter by pear and marquise shapes.

If you want a bigger stone without treatment

There are legitimate ways to buy size without paying for grades nobody sees:

• Choose SI1 clarity in a brilliant cut. Round, oval, pear, marquise, cushion and radiant cuts hide inclusions well. Check the plot on the certificate to confirm nothing dark sits under the table. Our guide to SI1 and SI2 clarity explains how.
• Drop a colour grade or two in a warm metal. In yellow or rose gold, H, I and J read as white.
• Choose an elongated shape. Oval, pear and marquise cuts spread their weight across a larger face-up area, so they look bigger than a round of the same carat weight.
• Use a halo or cluster. Small accent stones make a modest centre stone look considerably larger.

Frequently asked questions

Is a clarity enhanced diamond a real diamond?

Yes. It is a genuine diamond that has had a treatment applied to make its inclusions less visible. What is altered is the appearance, not the identity of the stone.

Do clarity enhanced diamonds last?

The diamond itself lasts indefinitely — it is still the hardest material there is. The treatment is the question. Laser drilling is permanent. Fracture filling is not: heat from repairs, some cleaning methods and time can all damage it, and it may need redoing.

Can a jeweller tell if a diamond is clarity enhanced?

Yes. Under magnification, fracture filling gives a characteristic flash of orange, purple, pink or blue along the treated fracture, and laser drilling leaves a visible fine channel. Any competent gemmologist will spot both.

Do clarity enhanced diamonds hold their value?

Not well. They are valued against their original, untreated clarity, and many dealers will not buy fracture-filled stones at all. Treat one as a purchase to enjoy rather than an asset.

Can I clean a clarity enhanced diamond normally?

Warm water, a drop of washing-up liquid and a soft brush are fine. Avoid ultrasonic and steam cleaners and any harsh chemicals, and always tell a jeweller about the treatment before any repair involving heat.

Buying with your eyes open

Clarity enhancement is not a fraud when it is disclosed. It is simply a compromise, and one whose costs land on you later — in repair restrictions, in care restrictions and in what the stone is worth.

Every centre stone we set is a lab-grown diamond with a free IGI certificate, untreated, hand-set in solid gold or platinum in North Harrow, London, with free insured UK delivery and 30-day returns. If you want a particular size and clarity that you cannot see in the collection, we design bespoke pieces at no extra design cost — tell us what you are trying to achieve and we will be straight with you about what is possible.