The Mystique of the Crystal Skulls

The Crystal Skulls are a series of objects carved from white quartz (or rock crystal) in the form of human skulls, which some claim come from pre-Columbian cultures of Central America. However, none of the objects made available for scientific examination have been confirmed to be of pre-Columbian origin.
Indeed, the results of the analyses have, if anything, shown that the skulls examined had been manufactured during the mid-nineteenth century, almost certainly in Europe during the period of interest in ancient cultures. Despite what has been written in popular literature on the skulls, especially in reference to their alleged mystical powers, they are not mentioned in Central American mythology or in that of the American Indians.
Some members of the New Age movement claim that these skulls are capable of producing paranormal phenomena, but not even this has been conclusively proven.
There are several skulls preserved in various parts of the world, and each with its own story:

The Mitchell-Hedges Skull - Perhaps the most famous and enigmatic artifact, which seems to have been discovered in 1924 by Anna Mitchell-Hedges, the adopted daughter of the famous British adventurer and author F.A. Mitchell-Hedges.
This finding was the subject of a video documentary filmed in 1990 (Crystal Skull of Lubaantun.)
The skull was examined by Smithsonian researchers who described it as "A replica very close to the British Museum skull, almost exactly the same shape, but with more detail on the eyes and teeth.
Mitchell-Hedges claimed to have found the skull buried under a collapsed altar inside a temple in Lubaantun, in present-day Belize. As far as it has been possible to ascertain, F.A. Mitchell-Hedges himself never made mention of the alleged discovery in any writing on Lubaantun. Others present at the time of the excavations did not mention the discovery of the skull or even Anna's presence on the spot.
According to new evidence presented in the National Geographic documentary, the skull was bought at the Sotheby's auction by F.A. Mitchell-Hedges in London on October 15, 1943. Shortly thereafter, he spoke of the purchase in a letter to his brother.
The skull is made from a block of clear quartz the size of a small human skull. It measures 13cm high, 18cm long and 13cm wide. The jaw is detached. In the early 1970s it was temporarily kept by the restorer Frank Dorland who, upon inspecting it, said that it had been "sculpted" without the slightest regard for the natural axis of the crystal and without the use of metal tools. Dorland added that he had not been able to find any scratches or abrasions, except for traces of mechanical leveling of the teeth. He hypothesized that the object had first been chiseled into a rough shape, probably using diamonds, while the work of refining the shape, leveling and cleaning would have been achieved through the use of sand over a period of 150-300 years. .
Dorland said it might as well have been 12,000 years old. Although the skeleton has been said over the years to possess particular physical properties, including a constant temperature of 21 °C (70 °F), Dorland said he found no differences between the skull's material and other crystals quartz.
While the skull was in Dorland's custody, it attracted the attention of writer Richard Garvin, who at the time worked in an advertising agency and oversaw the promotional campaign for Hewlett-Packard. Garvin requested and was granted permission to have the skull analyzed by Hewlett-Packard's crystal labs in Santa Clara, California.
The various tests conducted in the laboratory showed that the object was not obtained in the way Dorland hypothesized, but modeled on a single quartz crystal.
Tests established that the lower jaw had been machined from the same crystal. Hewlett-Packard did not continue in further testing.
Regarding the leveling traces on the teeth, archaeologist Norman Hammond argued that the notches (presumably used to support the object) have the characteristic signs of contact with metal tools. Anna Mitchell-Hedges refused any subsequent requests to subject the skull to further scientific testing.