How To Tell If You Have a Meteorite or Just Another Rock

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We all come across strange looking rocks that just seem out of place. Could it be a meteorite?

It’s a really common question for many people who find peculiar stones, However, the likelihood of actually stumbling across a meteorite is slim, with less than 1% of suspected rocks actually being meteorites!

How To Tell If You Have a Meteorite or Not

To determine if you’ve truly found a piece of the cosmos, there are a few straightforward tests you can carry out on-site before approaching a university or laboratory for verification.

Armed with a magnet, a grinder or file, and a magnifying glass, you can start the identification process right away.

Start with the magnet test to detect any magnetic, iron-rich components. Use a strong magnet, preferably suspended on a string to enhance its sensitivity, and approach the rock to the magnet.

Following this, the surface test checks for textural features consistent with meteorites, such as a lack of holes and the presence of a fusion crust.

Lastly, the window test involves grinding a small flat area on the rock to reveal its internal structure, potentially showing iron flecks or spherical chondrules. It’s important to note that while these tests can indicate potential, they are not foolproof and further confirmation may be required.

Remember:

  • Less than 1% of rocks suspected to be meteorites actually end up being a meteorite.

Tests To Identify Meteorites

Necessary Equipment

When investigating an unidentified stone suspected to be a meteorite, properly equipping yourself is crucial. There’s only a few things you need to have on hand:

  • Magnet: Obtain a strong, preferably rare-earth, magnet that has a high capacity to attract metals. To enhance sensitivity, suspend it from a string.
  • Grinder or file: This could be a diamond file for manual grinding or a battery-operated drill with a grinding attachment for creating a flat surface on the stone.
  • Magnifying Glass: Use this to closely examine the outer characteristics and the inner makeup of the rock after grinding.

Magnetic Attraction Test

Conduct an initial check for iron by using a magnet. Obtain a strong magnet such as a rare-earth magnet, which resembles small, coin-shaped batteries. For improved sensitivity, suspend the magnet from a string. Move the rock to the magnet’s vicinity; if the magnet sways towards the rock, this indicates the presence of iron. However, this alone does not confirm that the rock is a meteorite, as many Earth rocks also contain iron. It simply just tells you the stone contains iron.

Surface Test

Carefully observe the stone for any metallic-looking grains on its surface or contraction cracks indicative of meteoritic descent. Watch for a dull, burnt coating known as a fusion crust — a common feature on newly fallen meteorites. Look for a smooth overall surface without voids or rough, sharp edges.

Closely inspect the rock’s surface with a magnifying glass, searching for these specific features:

  • Texture: The surface should be somewhat rough with no sharp edges or holes.
  • Metallic Speckles: Look for tiny iron flecks.
  • Fusion Crust: Fresh meteorites have a black, burnt outer layer called a fusion crust.
  • Contraction Cracks: Fresh stones might display cracks from cooling but remember, holes negate meteorite possibility.

Window Test

By grinding a small, flat area onto the rock, you can inspect the innate structure or matrix within. Seek out shiny iron flecks or the presence of chondrules, which look like tiny, spherical inclusions that differ in color from the surrounding material. The absence of these features may point away from a meteoritic classification.

Create a flat spot on the rock’s surface to examine its interior matrix:

  1. Use a grinding tool or file to polish a small area, approximately the size of a thumbnail.
  2. Analyze for:
    • Iron Flecks: Even if weathered, some iron flecks should be visible.
    • Chondrules: Rounded, off-colored inclusions within the matrix could indicate a meteorite.

Remember, observing these characteristics provides preliminary evidence and may warrant further investigation from a specialized laboratory or university.

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