Not really.
Synthetic diamonds can be readily detected by at least two instruments sold by De Beers.[1] They look at emissive and absorptive optical features that aren't due to impurities, but due to defects (vacancies, stacking faults, interstitials, etc.). These crystal defects are atomic-scale departures from lattice perfection that are inherent to high growth rates (compared to natural diamonds). You can't see them on visual inspection.
These machines are expensive, even when sold at De Beer's cost. You won't see them in the corner jewelry store. But for stones > a carat, it's worthwhile to send a gem to services that use these machines to determine whether the stone is, for example, a natural type IIa (the purest of natural diamonds) or a potential synthetic that "needs further characterization".
[1] https://www.iidgr.com