A type of rock that people
often mistake for meteorites are those composed of iron oxides like hematite and magnetite because such
rocks are denser than most common rocks. Hematite
and magnetite can be recognized by the streak test.
Streak is a word referring to
the color of the streak that a rock makes when it is scraped against the unglazed side of a white ceramic
tile (or, the unglazed bottom of
a white coffee cup or toilet tank cover). Hematite makes a rust or
blood-red colored streak; magnetite makes a dark gray streak. Hematite and
magnetite streaks are easy to make, almost like chalk on a sidewalk.
If you get a
red streak or a gray streak like those in the photo, the rock is not a
Another “test” for hematite
is that when a hematite-rich rock is cut with a rock or tile saw, the wash
water turns bright rusty red.
Meteorites give no streak or only a weak grayish streak, but only if you press
hard. Also, any terrestrial igneous rock will not give a streak, so absence of a streak does not
indicate that the rock is a meteorite.