Found this while using StumbleUpon and thought it may be of interest to people who buy this kind of thing.
I am a collector of crystals, minerals and fossils I have indeed been fooled by one or two of these in my time so it's always handy to be forewarned so-to-speak.
The Vug; Fakes, Forgeries, and Misrepresentations in the mineral world
Would be exceptionally interested to see more pages of this kind on this thread so we can be guided away from the shamsters and fraudsters who want to make a quick buck out of unsuspecting people and quite frankly should be stopped!
There's also a blog: FakeMinerals.com