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Stone
Meteorites are the most diverse group of meteorites and are
the most common meteorite to enter the atmosphere yet they
are rarely found as they are hard to distinguish from native
rocks and often decompose or shatter on impact making them
hard to identify after a few thousand years.
There
are two main groups of stone meteorites, the Chondrites and
the Achondrites. Chondrules is derived from the Greek word
for seed and represents the small nodules of silicates that
are found in these meteorites. The nodules may vary from microscopic
to 20mm or more and make a rock similar to our conglomerates.
Achondrites are stone without the presence of these nodules.
Chondrites are estimated to have been formed in the beginnings
of the solar system some 4.5 billion years ago. Both forms
of meteorites may also contain some amounts of iron. Achondrites
may sometimes resemble Chondrites but the nodules have occurred
due to crystallization of minerals on cooling rather than
through the collection of small fragments that fuse together
to form a Chondrite.
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