Hope of retrieving Malta's stolen moon rock seems to be fading after Heritage Malta admitted that no progress has been made to retrieve the pea-sized rock.
Talk that the Malta rock had found its way to a Christie's auction in New York has been dismissed as "false" by a Nasa curator.
And retired Nasa inspector Joseph Gutheinz reiterated his appeal to the police to announce an amnesty programme and a "no questions" scheme to try and get the precious rock back.
The dull-grey specimen, embedded in a clear acrylic ball, estimated by some experts to be worth up to $5 million, was stolen from the National Museum of Natural History, in Mdina on May 18.
The rock - a 3.9 billion-year-old lunar sample - was picked up by Apollo 17 astronauts Eugene Cernan and Harrison Schmitt from the moon's Taurus Littrow Valley during their mission in December 1972.
In 1973, then US President Richard Nixon had given identical moon rock fragments as "goodwill" gifts to 135 nations.
The Malta case has whipped up a frenzy in the astronomy world to the extent that at least two American enthusiasts have been prompted to initiate a project to track down the moon rocks around the world.
Foreign media reports say the theft has re-ignited interest in moon rocks, along with a sizzling market for space collectibles overall.
Heritage Malta chairman Mario Tabone said the police had reported no developments in the case of the stolen rock.
He said it was ironic that the rock was stolen when a detailed security report of all sites managed by Heritage Malta had just been completed. Full-time security managers would be employed shortly.
Asked whether the police were contemplating implementing an amnesty in the hope of retrieving the rock, Dr Tabone said this had not been done.
"We have to keep in mind that once the case has been reported to the police, then it's automatically considered a crime. The Attorney General would have to be roped in to order an amnesty, since you are actually talking about a change in the laws."
Earlier this month, Christie's in New York was auctioning a wristwatch, which was supposedly worn by Lt General Thomas Stafford on Gemini Vl and Apollo X, together with a moon rock matching the dimensions of the one reported missing from Mdina.
When The Times contacted Christie's to find out whether it could be the Malta rock, a spokesman said the lot had been withdrawn and the rock had been sent to Nasa for further investigation.
Contacted at the Nasa Johnson Space Centre, moon rock curator Gary Lofgren said that tests had confirmed that the rock withdrawn from Christie's was not the one stolen from Malta.
He would not attach a price tag to the missing rock. "It's a collector's item and such items are worth as much as collectors are willing to pay for them," he said.
Ultimately, though, those responsible for its theft are going to have trouble selling it, Dr Lofgren pointed out. "The minute they try to do so, it'll get confiscated. Where do they go? That rock is too hot to handle!"
He would not pass judgment on Malta's security standards but said that most people did not realise the real worth of such items until they went missing.
Dr Lofgren said he was aware of one other moon rock that had gone astray in Sweden and one in Honduras had been retrieved after a sting operation.
In 1998, Mr Gutheinz and other federal officers staged an elaborate operation designed to smoke out dealers in black market lunar rocks and in the process landing them the Honduras rock.
When Mr Gutheinz initiated Operation Lunar Eclipse, conmen were preying on the naive and selling them dirt and rocks, which they claimed came from the moon.
"I'm concerned that in light of the Malta moon rock theft, people from Malta and Europe could be buying phoney versions of this Malta moon rock for the next 20 years," Mr Gutheinz told The Times.
The con-artists will go to events frequented by collectors, like Star Trek conventions and high society parties.
There are two types of moon rocks sold at auction houses. First, there are moon rocks the seller claims came back from one of the Apollo missions or one of three unmanned Soviet missions. Then there are meteorites alleged to be from the moon and found in remote places on earth.
An alleged moon rock meteorite was recently being sold on E-bay.
Recent media reports said that nobody, including Nasa, seemed to know the precise whereabouts of most of those fingernail-sized samples.
In 2002, three Nasa interns stole a 600lb safe with reportedly 3.5 ounces of moon rocks inside, valued at tens of millions of dollars.
The Apollo moon rocks are the most desirable because of the emotional connection millions of people made when they watched on TV as astronauts collected the rocks.
Robert Pearlman, editor and founder of Collectspace.com, a source for space-memorabilia enthusiasts, estimated that a piece of Apollo gravel weighing 4/100ths of an ounce would be conservatively worth $1 million. That is roughly four times the price of a diamond that size.