Lab-grown diamonds vs moissanite.

No. It is one of the most common questions we get, and the short answer is that moissanite is not a diamond of any kind — mined or lab-grown. It is a different stone entirely, silicon carbide (SiC), while a diamond (mined or lab-grown) is pure carbon.

Almost every moissanite sold today is grown in a lab, which is probably why the terms get tangled. But "lab-grown" describes the origin, not the material. A lab-grown diamond is diamond. A lab-grown moissanite is moissanite. They are chemically distinct, and they look and price differently on the finger.

A lab-grown diamond has the same crystal structure and the same chemical formula as a mined diamond: pure carbon, grown by HPHT or CVD. Grading labs like IGI test and certify them on the same 4Cs scale used for mined diamonds.

Moissanite is silicon carbide, originally identified in a meteor crater in 1893 and since produced synthetically. It has its own crystal system and its own optical fingerprint. Diamond testers made for carbon-based stones can misread moissanite unless they are the newer dual-tester kind.

Diamond returns light in a balanced mix of white flashes (brilliance) and coloured flashes (fire). Its refractive index is about 2.42. That balance is a big part of why a well-cut diamond reads clean and bright on the hand.

Moissanite has a higher refractive index of about 2.65 and roughly twice the dispersion of diamond. The result is more coloured fire, especially in sunlight, sometimes described as a rainbow or disco flash. Some people love it. Some prefer the quieter, whiter sparkle of diamond. Neither is wrong. It is a look preference.

Diamond is a 10 on the Mohs scale, the hardest natural material known. Moissanite is 9.25, which is still very hard and well suited to everyday wear. Both stones stand up to a lifetime of daily use when set properly.

In practical terms, either will resist scratching from almost anything you meet day to day. Diamond has the edge in the very long term, but moissanite is more than durable enough for an engagement ring you plan to wear every day.

At the same size and quality, moissanite costs meaningfully less than a lab-grown diamond, which in turn costs meaningfully less than a mined diamond. A one-carat-equivalent moissanite often sits in the low hundreds. A one-carat lab-grown diamond of comparable cut and clarity typically runs in the low thousands. A mined equivalent multiplies from there.

Price alone should not decide the stone. Decide the look first — diamond's balanced sparkle or moissanite's rainbow fire — and then use price to size and specify the stone you actually want.

Choose a lab-grown diamond if you want a real diamond, graded on the same 4Cs as mined diamonds, with a certificate and a laser inscription — but with a clearer origin story and a fraction of the mined-diamond price. Every stone in the Harlow Vault is a lab-grown diamond for exactly these reasons.

Choose moissanite if you like a more colourful, playful sparkle and want to stretch your budget the furthest. Moissanite is its own beautiful stone. It is not a diamond, and it is not a fake — it is moissanite, and it does not need to pretend to be anything else.