Meteorites, the rock-like specimens which have come to our earth as
sparkling meteors in the sky, are perhaps the most prized specimens
which the average collector hopes to find, and perhaps more specimens
are mistaken for meteorites than for any other geological substance.
Meteorites are rare and not easy to find; they are also not easy to
determine.
The iron variety is usually a heavy, roughly-pitted, brown, tough,
metallic, nickel alloy of iron. Therefore, a positive chemical test for
nickel is usually strongly suggestive of a meteoric origin, but
confirmation almost requires that a surface be polished and etched with
dilute acids to bring out typical and characteristic structures.
[Illustration: The polished and acid-etched surface of an iron
meteorite. Shows the Widmanstatten figures characteristic of iron
meteorites. (Photo courtesy of American Museum of Natural History,
New York).]
The stony variety of meteorites usually contains a rock-forming mineral
called olivine, beneath its pitted brown surface. In case of either
variety, since special equipment is required for final testing and
determination, it is recommended that this be done at a laboratory
appropriately equipped.