Fragments of a meteorite that landed in California last week are much more interesting because of their composition than first thought, scientists say.

Meteorite hunters found fragments after the meteor was sighted streaking through the sky April 22 and exploding in a fireball.

NASA and the SETI Institute in Mountain View, Calif., mobilized a search team last weekend to look for the fragile black rocks.

The fragments recovered showed the meteorite consisted of a very rare type of rock called CM chondrite, which makes up less than 1 percent of the meteorites that fall to Earth, NewScientist.com reported Tuesday.

CM chondrites contain carbon and organic materials such as amino acids, and some scientists have said they believe this type of meteorite may have brought the first building blocks of life to Earth.

A large CM chondrite that fell to Earth in Australia in 1969, known at the Murchison meteorite, is now one of the most studied rocks in the world for that reason, researchers said.