I do hope that Blizzard implements some sort of searching convention specific to the socketable gems that jewelcrafters make. I am wearing a couple of these items (or at least will once I grow tired of my awesome pointy red witch hat and re-equip the better headpiece I have) and well... they're totally overvalued if you don't actually... fill the sockets. The problem is, I have no idea what the gems that can go into them are, what they are called, any of that info. I've done quick searches on this here internet and have been unable to come up with what I want: a quick and dirty reference item of what all socketable gems exist. What they are named and what they do and what 'color' they are, mostly.
So as it stands, the only real option I have is to either suck up the valuable time of a jewelcrafter asking noobish questions about their craft or scan pages upon pages of... you guessed it, trade goods in the auction house looking for anything weird that might be a socketable gemstone. Even then, it seems as though the current selection in the AH is lean and more often than not, gems for useless things like strength and plus stab or something. pfft!! Who would want that?!?!
Now I wouldn't complain too loudly about this, but think about it... trade goods are consumeables that used to make a finished product via crafting. Socketable gemstones on the other hand are the finished product. They don't belong in the trade goods listing. I mean, not logically, at least. Oh well, I'll figure it out. :p