I was given a lot of hydrothermal gems as a gift recently. Basically they are gems but they are labgrown. They are made of the same material though as in nature and the growth methods are replicated. Instead of growing over millions of years they grow in months under immense heat and pressure in tubes.
Personally I would never have bought them but as a present I welcomed them in my collection. They are so shiny and sparkly!
I can see why a lot of people will be put off by them and I doubt they'll have any metaphysical value although some books mention Syberian Blue Quartz which is also labgrown. Another thing is that by growing gems this way nature doesn't get disrupted as no mining is needed. That is a good thing.
I think I'll need some more time with them to think about thow I feel about hydrothermals. They sure are pretty, photos don't do them justice at all.