By Dr David Whitehouse
BBC News Online science editor
A rock found in the Atlas Mountains of southern Morocco in 2001 has been confirmed as Martian in origin.
Carine Bidaut and Bruno Fectay hold rocks from Mars
The meteorite's chemical signature was checked out by researchers at the UK's Southampton Oceanography Centre.
The team that found it was led by experienced meteorite hunters Carine Bidaut and Bruno Fectay, who have now found six rocks from Mars - a record.
The meteorite would have been blasted off the Red Planet by an impact and may hold clues to Mars' watery past.
It was picked up by a local worker on an isolated plateau in the mountains at a location which is now being kept secret because of fears it may be spoilt by visitors.
"For 30 years the locals have been searching the region for fossils so they know the area very well," Bruno Fectay told BBC News Online. "A few years ago we taught them to look for meteorites.
"The rocks of the region are mostly light in colour whereas meteorites are dark, so they can be easily spotted."
The meteorite - although in two fragments, it is classified as the same body - has been officially called the North-West Africa 1950, but has been nicknamed the Jules Verne, after the French author.
It is described as a peridotite, an extremely rare type of Mars rock consisting of the minerals olivine, pyroxene and plagioclase glass.
Scientists say the fragments are magmatic rocks. Magmatism is the main process by which water moves from the core of planets to their surface.
"It is a remarkable experience to hold it in your hand," Bruno Fectay said. "When you hold it you are in a Martian magmatic chamber, deep in a volcano under the surface of Mars.
From a magma chamber below Mars
"We will never be able to go to such a place. This rock is our passport."
Further analysis will help clarify the processes that produced magmas on Mars, and perhaps make it possible to estimate the quantity of fluids - and therefore water - released by volcanic activity on the planet in the past.
Life on Mars
Mars meteorites are extremely rare - fewer than 20 confirmed examples have been identified - and all are believed to come from the same body of rock that was blasted off the planet when it was hit by a large asteroid or comet.
They have travelled through space and then fallen to Earth.
Martian meteorites are distinguished by their relative youth, being at most 1.3 billion years old, compared with 4.5 billion years old for other meteorites.
They also show evidence of rare gases found in the planet's atmosphere.
In 1996 a team of scientists from the US space agency Nasa controversially claimed to have found evidence of past life in a meteorite from Mars.
Although they have been exposed to the Earth's weather and contamination from its biosphere, Martian meteorites open a new way to study Mars because they are basaltic rocks formed in the presence of water and so illuminate the story of water on Mars.
More to follow
Only one other example of a so-called SNC meteorite equivalent to NWA 1950 has been found on Earth - a chunk of rock discovered in Antarctica in 1977.
And apart from Nasa, no other scientific laboratory has had the opportunity to examine such a specimen.
Bidaut and Fectay have a stock of over 1,000 meteorites waiting to be taken up by financial sponsors so they can be examined in European labs.
"It takes us a while to get our finds analysed," said Bruno Fectay. "We may have more of the remarkable meteorites from Mars waiting to be examined."