That's because Orro sells lab-grown diamond
simulants and not lab-grown
diamonds.
Lab-grown diamonds are identical to naturally-formed diamonds in composition, just that they are formed by a different process. IIRC (but don't quote me on this), true lab-grown diamonds (NOT LAB-GROWN DIAMOND SIMULANTS) are almost 100% indistinguishable from naturally-formed diamonds, except when examined under specialised tools, because the different method of formation affects the way the carbon atoms join together or something like that. Lazy to explain so here's a link to GIA -
Personally, if I were buying for myself (like if I were the type to wear some massive diamond ear stud 2000s beng style), I wouldn't mind getting lab-grown diamonds.
But for an engagement ring, I rather err on the side of caution and just get a naturally-formed diamond unless I am 99999999% sure my GF would rather I save the money and get a lab-grown diamonds
But like I said previously, be mindful of the difference between synthetic diamonds (or lab-grown diamonds) and diamond simulants. While we are all accustomed to the traditional jewellers giving misleading information on the good old naturally-formed diamonds, don't believe for a second that all alternatives to natural diamonds are created equal. True synthetic diamonds, especially the CVD synthetic diamonds, are still quite hard to find in Singapore.