system
A chat on subreddit /r/me_irl
human
I work in cs for a company that has sold lab-grown diamond jewelry at times and we get returns for these like "oh, my local jeweler said these aren't real diamonds.."  Ah yes and I bet he then upsold you significantly on something they offered.
gpt
A lot of jewelers deliberately obfuscate the difference between lab-created and imitation gemstones (i.e. where the gemstone is not the same mineral as advertised, e.g. like glass) because they get the bigger mark-up on the natural stones and want you to think lab grown ones are fake.