Lab-Grown vs Moissanite vs Cubic Zirconia: An Honest Comparison

If you are choosing a stone for a memorial piece, you will be offered three things that look similar and are not similar at all. They get grouped together constantly, and almost all of the grouping is misleading.

Here is the honest version.

The distinction that settles most of it

A lab-grown diamond is a diamond.

It is not an imitation of a diamond, and it is not a diamond lookalike. It has the same chemical composition (carbon), the same crystal structure, and the same optical and physical behaviour as a mined diamond. The only difference is where it formed — underground over billions of years, or in a laboratory in a few weeks.

Moissanite and cubic zirconia are different materials that resemble diamond. In gemology they are called simulants.

Those numbers explain everything you will ever observe about how the three stones behave.

Hardness: the number that decides durability

Mohs 10 means diamond is the hardest natural material. Nothing scratches it except another diamond.

For a memorial piece, this is not a luxury consideration. A ring worn daily for years touches desk edges, door handles, cuffs, keys and other jewellery. Hardness determines whether the stone keeps its crisp facet edges or slowly dulls.

• Diamond (10) — edges stay sharp indefinitely. Lifetime brilliance.
• Moissanite (9.25) — genuinely durable. Edges soften very slightly over decades. Visually indistinguishable from diamond in terms of wear.
• Cubic zirconia (8 – 8.5) — soft enough that ordinary contact leaves micro-scratches. On a CZ you can actually see surface abrasion build up in weeks to months. Polish dulls, transparency drops, the stone looks cloudy.

This is the practical argument. A memorial piece is not fashion jewellery. It is intended to last longer than you will.

Light performance: why diamonds don't look "too colourful"

This is the part most comparisons get backwards.

Lab-grown diamond produces the classic pattern: bright white brilliance, restrained fire, sharp scintillation. It reads as expensive because it is doing exactly what a diamond does.

Moissanite has roughly 2.5× diamond's dispersion. It throws noticeably more red, orange, green and blue. Under sunlight or a spotlight this is obvious. Some buyers love it. Buyers who pictured a diamond find it wrong.

Cubic zirconia has broader flashes and more fire than diamond, but because it is softer, it lacks that precise crispness. A new CZ can look surprisingly convincing at arm's length. It does not stay that way.

The visual test that actually works

1. Look at the stone in daylight first, then under indoor lighting. Differences that vanish under one appear under the other.
2. Compare stones side by side, never from separate photographs. Product photos hide more than they show.
3. Above roughly 0.7ct, the differences become visible to the naked eye without special equipment.

The single clearest tell: excessive rainbow = moissanite. Quick clouding with wear = cubic zirconia. Sharp consistent brilliance with controlled fire = diamond.

Price

Roughly, for comparable centre stones in comparable settings:

Lab-grown diamonds sit above simulants because they are grown by a controlled industrial process with real equipment, and because they are individually graded and certified. They are not cheap, and they are not meant to be.

For most memorial buyers the honest framing is: simulants are cheaper, and for a piece you intend to keep for decades, that saving buys a stone that will look tired.

Certification, and what a certificate proves

Lab-grown diamonds are graded by independent laboratories — for us, NGTC — and the certificate should state:

• The 4Cs (cut, colour, clarity, carat)
• That it is lab-grown, and the growth method (HPHT or CVD)
• Laser inscription on the girdle linking the stone to its certificate

A certificate from a recognised lab proves the stone meets graded specifications. It does not prove your emotional experience, and it should not be marketed as though it does.

Two cautions. A grading certificate proves what the stone is; it does not prove where the carbon came from. Traceability of the original sample is a separate record, and you should ask whether the provider keeps one. And "lab-grown" must be disclosed — a lab-grown diamond marketed simply as "a diamond" without disclosure is misrepresented, in the same way a moissanite passed off as a diamond would be.

If you are choosing a memorial piece specifically

Three things matter more than the price comparison:

1. Durability over decades. This is a keepsake meant to be handed on. That rules out CZ on physical grounds alone, and it is not close.

2. Honest labelling. Whoever sells it should say plainly whether the stone contains your pet's fur or ashes physically, or whether carbon was extracted from them and a new stone was grown. These are different products with different meanings, and conflating them is the most common source of later disappointment in this industry.

3. A traceable sample. You should be able to get your unused sample back. Ask before you send it.

Where a memorial diamond sits

Stated plainly, since we make these:

A memorial diamond is not a resurrection. It does not recover your pet or bring them back. It is an object of remembrance, grown from carbon that originated in them.

It is a genuine lab-grown diamond — same material, graded and certified, hard enough to last generations.

It does not contain your pet in any physical sense. No part of them is inside the stone. That is the honest boundary, and we would rather state it clearly than let anyone imagine otherwise.

Read next

• What to do with your pet's fur after they die — where the material for a memorial stone comes from
• Human hair memorial diamonds: the consent process — who has to authorise the material
• Pet funeral ideas in Singapore — the full farewell guide
• Whether a memorial diamond can bring a pet back — the honest answer
• Memorial jewellery in Malaysia: where to buy and what it costs — channels and real MYR prices

About FURLUM

We grow lab-grown diamonds from pet and human hair. Every centre stone is independently graded and certified by NGTC, and ships with a traceability record tied to your sample number. Unused sample is returned on request at no charge. Every stone is labelled as lab-grown, everywhere.

Comparison figures reflect published gemological data for ideal-quality stones; individual stones vary with cut and clarity. All stones compared here are disclosed lab-grown or simulant materials — none is presented as mined diamond.