How to Tell if the Rock You Found Might Be a Meteorite

Most rocks people think are meteorites really aren't. Here's how to avoid wasting a geologist's time with a rock that is not a meteorite, or avoid wasting money buying a "Meteorite" on eBay.

Steps

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    Grab a refrigerator magnet. See if the rock is attracted to the magnet. Most, but not all, meteorites will be attracted to a magnet.
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    Try to determine if the rock is significantly heavier than other rocks of the same size. Again, many meteorites are heavy for their size.
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    Examine the outer skin of the rock. Meteorites will have a "Fusion Crust" that usually has a darker color than the interior of the rock.
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    If the crust is more than a couple of millimeters thick, it's not a meteorite.
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    File or sand a side or corner of the rock. Is the inner color a metallic steel color? If so, it might be a Nickel-Iron meteorite.
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    Do a "streak test".[1] Rub the rock on a piece of unglazed ceramic (The back of a ceramic tile, or the rough bottom of a coffee cup). A meteorite will leave a weak or light streak. If it makes a red or brown streak, it's not a meteorite.
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    Look for holes or bubbles in the rock. If it has these, it's not a meteorite. It's probably a piece of industrial slag, or a volcanic rock.
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    Look for regmaglypts. Commonly known as "Thumbprints", these are impressions on the outer surface of a meteor that look like the thumbprints you might make in a piece of clay.[2]
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    If it's long and skinny, angular, spherical, square, or rectangular, it's not a meteorite.
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    Try to scratch it with a knife blade. If it does not scratch, it's probably not a meteorite.
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    If it has layers, it's not a meteorite.
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    If you have a rock with several meteorite characteristics (Fusion Crust, "Thumbprints", magnetism, heavy, metallic appearance, softer than a knife blade, weak or no streak), and none of the non-meteorite characteristics (Bubbles, wrong shape, layers, thick crust or no crust, harder than a knife blade, red or brown streak), see an expert. You may have a meteorite.

Tips

  • There are plenty of good books and websites out there. Educate yourself.
  • Your chances of finding a real meteorite are very small. Deserts are the best places to look, though.
  • Meteorites do have bubbles and they are called vesicles. All lunar meteorites are vesicular. Stony and iron meteorites do not have bubbles on the INSIDE. Some stony meteorites have air bubbles on the outside.

Warnings

  • Don't try to sell your rock on eBay as a meteorite unless it's been verified by an expert. eBay will not allow you to list something as "may be a meteorite".

Article Info

Categories: Rock Gem Mineral and Fossil Collecting