By Dr David
BBC News Online science
Scientists say a new lunar mineral has been found in a meteorite from the Moon that crashed to Earth in 2000.
The Moon's surface is a mineral mosaic
The mineral is called hapkeite after the scientist Bruce Hapke who predicted the existence of the iron and silicon compound on the Moon 30 years ago.
Hapkeite is probably made when tiny particles impact the Moon at very high speeds, say Mahesh Anand and colleagues
Their investigation of meteorite Dhofar 280 is reported in the Proceedings of the National Academy of Sciences.
The formation of rocky debris and soil on the surfaces of airless bodies in space involves processes that are virtually non-existent on Earth.
This "space weathering", as scientists call it, includes the impact of micro-meteorites which crush and pulverise surface rocks on a minute scale.
The micro-meteorites are about 0.1mm or less in diameter, but because of their velocities, about 100,000km/h, they carry a great deal of energy that is transferred to very small areas.
A mineral map of Dhofar 280
The impacted surface is "flash-melted", vaporising metals and causing chemical and structural changes.
Hapkeite results from the deposition of iron and silicon in a 2:1 ratio.
Space weathering is a process that has been occurring on the Moon for almost four billion years and has altered the upper few centimetres of its surface.
Although hapkeite was first predicted to exist some 30 years ago, this is the first time it has been seen. Scientists think it could be a common ingredient of the lunar surface.