As far as blue topaz is concerned, lab created is now available. I was cruising eBay for rough blue topaz, and found some that looked very suspicious to me, with almost a botryoidal top surface, with sawn bottom and sides. Check out item #’s 292217268069, 292220153031, 302415305922, and 401385364614. Incidentally, that last one is the only one that admits to being lab created, the others make no mention of it. These are all approx 100 carat chunks in the $8-$10 price range. The price should be a tip off, along with the botryoidal termination. All of these are coming out of India.