Types of Meteorites
There are three general
types of meteorites, classified
according to the ratio of stony to
The relative abundances of
stony, iron, and stony-iron
represented by all
known meteorites (combined
observed falls and finds).
More than 44,500
different meteorites are know, of which
Stony meteorites. These
are, by far, the most common type of
meteorite. Stony meteorites are
made of primarily of silicate minerals,
similar to those in ordinary Earth
rocks, plus small quantities of metal.
The metal occurs as millimeter-sized
flakes scattered throughout the stony
matrix. Like earth rocks,
stony meteorites are brittle and would fracture if
struck by a hammer. The specimen
shown to the left below is a weathered
stony meteorite with a typical
Iron meteorites. These are
much less common, but their unusual
composition (nearly 100% Fe-Ni metal)
and great heft favor recognition by the
layman. Therefore, irons
meteorites tend to be overrepresented in
meteorite collections (compared to their
actual fall frequency). Iron
meteorite are strong and ductile; a
hammer blow will do little damage.
The middle specimen below has been cut
on the front side. The specimen
exhibits rust-colored crust and bright,
fresh metal on the cut face.
Stony-Iron meteorites. The
rarest type of meteorite, stony-irons, are composed of roughly
equal amounts of stone and metal.
The specimen shown to the right below is
a slice that highlights the boundaries
between stony material (darkly colored)
and bright metal.
The three main types of
meteorites: stony (left), iron (middle),
and stony-iron (right).