Meteorites

1) The Magnetic Test

Meteorites come in three basic styles; iron, stony and stony-iron. The majority of all specimens to date have high iron or nickel content, which means that a strong magnet will attach itself to the rock. Iron and stony-iron meteorites have been known to establish such a strong connection with magnets that it is difficult to separate the two. Stony meteorites, while not as iron/nickel rich as the other types, still have enough magnetism for a strong magnet to attach. It is important to remember that many rocks on Earth have magnetism similar to that described above and in some rare cases meteorites from the Moon and Mars have shown no magnetism at all, therefore more testing should be conducted.

Meteorite with a Strong Magnet
Photo credit: David Draper

2) The Weight Test

Meteorites are incredibly dense due to their high iron composition. Iron has a very high density, meaning a small amount of it weighs more than it looks like it should. A good measure for determining if the rock is a meteor is to compare an Earth rock of similar size and compare weights; the prospective meteor should be much heavier.

3) The Exterior Test

When a meteor descends through Earth’s atmosphere, an exceptional amount of heat is applied to it by our atmosphere. This will cause the surface of the meteor to melt and actually burn, forming a dark shell-like substance called fusion crust. Earth rocks cannot develop this feature. Other exterior features can include regmaglypts, small oval-shaped indentions similar to those made with a thumb in clay and flow lines, tiny rivulets of the melted meteor surface that have run along the exterior; they can be thinner than human hair so a magnifying glass may be needed. Identification of meteorites can also be ascertained by cutting off a corner or side of the rock to expose a fresh surface; if small metal flakes can be seen or the inside is completely shiny and metallic then it is a meteorite.