Though you can see a real crystal skull -- in fact, an entire calcified skeleton -- on a trip to the Actun Tunichil Muknal [2] "cave of the crystal maiden" in western Belize, people are still fascinated with the legendary skull of Lubantuun. Allegedly discovered in 1927 by Anna Mitchell-Hedges on her 17th birthday, the crystal skull is flawlessly crafted, spurring some to involve aliens in their theories. Hoax of not, Belize wants its skull back, which resides in Canada since Anna passed away in 2007 at the age of 100.
Read more: "Myth of the Crystal Skull" [3]
Here is the Crystal skull's entry in the Skeptic's Dictionary [4]
Links:
[1] http://www.moon.com/files/blog-entry-images/skl.jpg
[2] http://www.mayabelize.ca/maya/actun-tunichil-muknal.shtml
[3] http://www.ambergriscayenews.com/html/archives.php?p=060508#_st2
[4] http://skepdic.com/crystalskull.html