Great link! Thanks!
When you attend a mineral convention, it will be helpful to brush up on the geological side of stones first. If a stone has a new-agey name, find out what its scientific name is. If it has a copyrighted name (Azeztulite, for one, but there are multiple others), then find out what its scientific name is, as well. And be aware that the copyrighted names are most likely only available from one source: the person who owns the copyright. So you are not likely to find any of these stones being sold by other vendors, who legally CAN'T market their items under that name.
I mention this because there are going to be people and vendors who are interested in the scientific side of stones, who do not study nor adhere to any metaphysical beliefs whatsoever. In order to find the stones you are looking for, you will have to speak THEIR dialect, because they won't speak nor believe in OURS. They won't know what crystal helps with headaches nor have any clue what angelite, auralite, merlinite, Melody's Stone/Super Seven, Lemurian, etc. mean.
On the plus side, I have found that the people who are interested in the geological side of stones offer FAR more reasonable prices than a lot of metaphysical sellers, at least on eBay and online. Therefore, shopping at at geology-oriented vendors will save you money. Do your homework in advance, and you'll have more satisfactory results.