The "jewellers can't tell" is BS. Unless you put quotes around the jewellers (as most jewellers are now just importers/re-sellers). As someone who bought lab gr

The "jewellers can't tell" is BS. Unless you put quotes around the jewellers (as most jewellers are now just importers/re-sellers). As someone who bought lab grown diamonds for some custom made jewellery and had them tested by the best jeweller in town (one of the few true jewellers still remaining) they certainly can tell. The lab grown diamond passed every test except conductivity. The jeweller found this curious as usually if a stone fails conductivity it also fails, for example, refraction tests. A bit of research on this topic led me to discover that the lab grown diamonds have a slightly higher metal content than natural diamonds which makes them slightly more conductive. TLDR; A good jeweller with the right equipment can tell.