Three stones, three prices, and in a photograph they look more or less identical. The differences are real, but they turn up in places a product image can't show you.
American diamond
American diamond is cubic zirconia. The name is a South Asian trade term rather than a description, and there's no diamond in it, which is worth saying plainly because plenty of shops don't. Ours are precision-cut and come from South Korean suppliers, and they're what we use as standard across fashion and everyday pieces.
It's a genuine stone with genuine sparkle at a fraction of the cost of the alternatives. What it lacks is hardness. Cubic zirconia sits around 8 to 8.5 on the Mohs scale, so on a ring worn daily for years the facet edges gradually soften and it loses a little of its bite. On earrings and pendants, which take almost no knocks, that's close to irrelevant.
It's the right answer for pieces you'll rotate, for anything you want in three different colours, and for a gift where the design is doing the work.
Moissanite
Moissanite is silicon carbide, and it's what goes into most of our engagement rings.
At 9.25 on the Mohs scale it's harder than everything except diamond, which in practice means ordinary wear will not scuff it. Its refractive index is higher than diamond's, so it throws more coloured fire. Some people love that. A few find it slightly theatrical under harsh light, and it's the one thing worth knowing before you commit, because it's the only respect in which moissanite doesn't simply behave like a diamond. In daylight and normal indoor lighting nobody is going to look at your hand and know.
For a ring meant to be worn every day for decades, it's the option I'd choose, and it costs a small fraction of a mined stone of the same size.
Lab-grown diamond
Chemically and optically the same material as a mined diamond. Same carbon lattice, same 10 on the Mohs scale, same refraction, same certificates. Telling it apart requires specialist equipment; a jeweller's loupe will not do it.
Which makes the choice between this and moissanite less about performance than people assume. At that level you're splitting hairs on durability. The real reason to pick it is that it is a diamond, and for a lot of people buying an engagement ring that word carries weight that no amount of comparison-table reasoning is going to displace. That seems entirely fair to me and I've never tried to talk anyone out of it.
It's the most expensive of the three, and still far below a mined stone of the same specification.
How to actually decide
On many of our engagement styles you can switch between moissanite and lab-grown diamond on the product page itself, so you can see what the difference costs on the exact ring you want instead of in the abstract. That's usually more useful than any general advice.
Broadly: one ring you'll wear for the next thirty years justifies moissanite or lab-grown. Earrings for Eid don't, and the money goes further in the design.
Whichever you pick, it's set by hand into 925 sterling silver and finished in 21k gold or rhodium, which we've documented step by step if you want to see the bench work. The moissanite collection and the wider engagement ring range are the places to start looking.