Lunar soil is richer than previously thought, with traces of silver among the complex mix of elements and compounds found within one of the moon's craters, according to a new study.

Researchers at Brown University who analyzed particles of lunar dust kicked up by a NASA-engineered collision last year found a surprisingly rich mixture that, in addition to the silver, included water and compounds like hydroxyl, carbon monoxide, carbon dioxide, ammonia, and free sodium.

"This place looks like it's a treasure chest of elements, of compounds that have been released all over the Moon, and they've been put in this bucket in the permanent shadows," said Brown University geologist Peter Schultz, lead author of the paper appearing in the October 22 edition of the journal Science.

The lunar particles were kicked up when a NASA rocket slammed into the Moon about one year ago, allowing scientists an opportunity to learn about the composition of the lunar soil at the poles that never has been sampled.

The findings were from NASA's Lunar CRater Observing and Sensing Satellite, or LCROSS mission, a 79-million-dollar experiment in which the US space agency sent the emptied upper stage of a rocket crashing into the Cabeus crater near the Moon's south pole.

The rocket slammed into the crater at around 5,600 miles (9,000 kilometers) per hour, sending aloft a huge plume of material from the bottom of the crater that had been untouched by sunlight for billions of years.

The rocket was followed four minutes later by a spacecraft equipped with cameras to record the effects of the impact.

Last November, NASA released initial findings from the experiment, announcing that it had found a "significant amount" of frozen water on the moon.

Schultz noted in his study that Apollo space missions decades ago already had found not just trace amounts of silver, but also gold, on the near-side (Earth-facing side) of the Moon.

But the discovery of silver at Cabeus crater suggests that silver atoms throughout the moon have migrated to the poles.

But the relatively meager silver concentration detected at Cabeus "doesn't mean we can go mining for it," Schultz said.