With Indiana Jones and the Kingdom of the Crystal Skull about to erupt across our cinema screens, attention has once again been directed towards the real crystal skulls that have intrigued scholars for years. Some are tiny, only an inch or so high, while others, like the “Aztec” skull in the British Museum, are lifesized and often anatomically detailed.

Contrary to the belief held by many New Age devotees, something that will doubtless be enhanced by this summer's movie, none of the skulls appears to be ancient. Research by Dr Jane Walsh, of the Smithsonian Institution in Washington, has shown that not only were modern tools used to shape them, but also many extant specimens can be traced back to the same Victorian fraudster.

Reporting on her 16 years of research in the American journal Archaeology, Walsh notes that “not a single crystal skull in a museum collection comes from a documented excavation, and they have little stylistic or technical relation with any genuine pre-Columbian depictions of skulls, which are an important motif in Mesoamerican iconography”.

The first crystal skulls made their appearance in the early 1860s: they are small, usually not more than one and a half inches high, and the first to be documented seems to be the one in the British Museum, with others appearing in Paris and Mexico City over the next decade or so. This “first generation” of skulls is drilled from top to bottom, and may have been made from genuine pre-Hispanic crystal beads, which are known from archaeological contexts in Mexico; some may have been made as a memento mori, carved for the European market, with no intention to deceive.

The Paris crystal skulls came from Eugène Boban, who ran antiquities shops in Mexico City and then in Paris in the 1870s, and who produced the first of a “second generation” of skulls, lifesize and unperforated. Failing to sell it in Paris or Mexico, where it was denounced as a fake, Boban set up shop in New York in 1886 and sold the skull at auction.

Tiffany and Co bought it for $950 but a decade later sold it to the British Museum for the same amount. It became known as “the Aztec crystal skull” until modern workmanship was detected in the 1960s. Walsh, who recently examined it with an electron microscope, considers it to be a 19th-century European “invention” carved with modern lapidary's equipment.

What Walsh calls a “third generation” of crystal skulls surfaced in the 1930s. Sidney Burney, a London art dealer, purchased a life-sized skull almost identical to the British Museum's, but with a separate jawbone. The two were compared in the journal Man in 1936, and then a few years later Burney sold his specimen to Frederick Mitchell-Hedges, author of Land of Wonder and Fear, Battles with Giant Fish and similar works high in adventure and short on veracity.Although Mitchell-Hedges never said where he got the “skull of doom” - in his 1959 autobiography Danger My Ally, he portentously claims that he must not reveal its source - as soon as his daughter Anna inherited it, it acquired a spurious Maya provenance that has clung to it for the past 50 years. She claimed to have found it at the site of Lubaantun in southern Belize and her story remained baseless until her death last year at the age of 100.

When I worked at Lubaantun in 1970, she wrote to me asking why I had not mentioned the skull in my reports, and built up a cottage industry taking it round US cities to display on a pay-per-view basis in rented hotel rooms. On the one occasion when I met her - and the skull - she claimed that the two metal-drilled holes under the jaw, to hold the artefact firmly in its box, had been there when she “found” it in the 1920s.

A considerable New Age literature, fuelled by a “skullie” cult, has built up around the Burney/Mitchell-Hedges skull and may well have inspired part of the new Indiana Jones movie. Walsh calls it “a veritable copy of the British Museum skull, with stylistic and technical flourishes that only an accomplished faker would devise”. The skulls are “too good to be true,” she says. Pre-Columbian lapidaries used stone, bone and wooden tools with abrasive sand - crystal skulls are much too perfectly carved and highly polished to be believed.

One puzzle remains: where did Eugène Boban get the relatively flawless blocks of rock crystal? Modern sources include Brazil and California, and Qing Dynasty China also produced large crystal artefacts. Until recently the undesirablility of drilling samples from the frangible crystal for analysis had precluded further source characterisation, but the advent of non-invasive Raman spectroscopy using portable machines may soon strip the last layer of mystery from this tale of skulduggery.