Listen. There's a cave somewhere in this world (I forget exactly where) that has such rare and exotic things, that it's completely off-limits to ordinary explorers. The reason is so that none of the specimens get damaged or disturbed while the scientists continue to investigate the strange nature of what's down there.

For all we know, there could be irridescent crystals down there. just because nobody's seen them, doesn't mean they don't exist. people find rare oddities all the time. Look at the undersea discoveries that take place.