I stumbled upon the original site and am totally confused. Although the site seems legit, the size of these things seem too big from my understanding of crystal formation. Crystals coalesce slowly, from the inside out (so to speak) and bottom to top. They do not form like stalactites or stalagmites, where there is a dripping accumulation. It seems that a crystal of that length would break before becoming thick enough to sustain its own weight. I called a professor of geology at the local university. He had never heard of the caves and was also skeptical of their size. He didn't ask for the URL, though, so he never saw the photos.
Regarding the photos, they do seem real at first, but now some seem to be doctored. I don't know...