Meteorites: How to Identify Them — A Detailed Guide
Meteorites have fascinated humanity for thousands of years. These extraterrestrial rocks survive their fiery journey through Earth’s atmosphere and land on the surface, offering a rare glimpse into the early solar system. Because they can resemble ordinary Earth rocks, proper identification is essential for collectors, scientists, and rockhounds.
This guide provides a clear, detailed breakdown of meteorite characteristics, testing methods, and common misconceptions to help you determine whether that mysterious rock might truly be from space.
What Is a Meteorite?
A meteorite is a solid piece of debris from an asteroid, comet, or even another planet that survives passage through Earth’s atmosphere and lands on the ground.
There are three main types:
- Stony Meteorites (Chondrites & Achondrites) – Most common; contain silicates and sometimes metal flecks.
- Iron Meteorites – Composed mostly of iron and nickel; very dense and magnetic.
- Stony-Iron Meteorites (Pallasites & Mesosiderites) – A mix of metal and silicates; often visually stunning.
Knowing which category your potential find might belong to helps narrow down its identification features.
Key Characteristics of Meteorites
1. Fusion Crust
Meteorites typically display a thin, dark outer layer formed when the surface melts during atmospheric entry.
- Usually black, brown, or dark gray.
- Smooth or slightly glossy.
- May show “flow lines” or rippled textures.
Earth rocks rarely have this type of melted, glassy crust.
2. Regmaglypts (Thumbprints)
Especially common on iron meteorites, regmaglypts look like thumb-sized impressions on the surface.
These form as the meteorite ablates during descent and are a strong identifying feature.
3. Density & Weight
Meteorites—particularly iron and stony-iron types—are noticeably heavier than ordinary Earth rocks of the same size.
- Iron meteorites: extremely dense
- Stony meteorites: moderately dense
Pick it up—weight can be your first big clue.
4. Magnetism
Most meteorites contain iron-nickel metal, making them strongly magnetic.
- A basic magnet test is often the quickest way to eliminate many Earth rocks.
- Note: Some volcanic rocks are also magnetic, so this test alone isn’t proof.
5. Metal Flakes or Veins
Stony meteorites often show:
- Metal flakes (iron-nickel)
- Tiny metallic specks mixed within the rock
These do not glitter like mica. They appear dull, silver-gray, or metallic and are usually scattered evenly.
6. Chondrules (in Chondrites)
Chondrules are small, spherical mineral grains unique to certain stony meteorites.
- Visible in broken or cut sections
- Round to oval
- Typically millimeter-sized
If you see chondrules, you likely have a meteorite.
7. No Quartz
Meteorites never contain quartz crystals.
If you see:
- clear crystal patches
- glassy quartz veins
You can rule out a meteorite.
8. Interior Color & Texture
The interior of a meteorite differs depending on type:
- Stony meteorites: gray matrix with metal specks, sometimes chondrules
- Iron meteorites: solid metallic interior
- Stony-irons: vibrant contrast of metal and olivine crystals (in pallasites)
Cutting or breaking a small piece can help confirm its identity.
Simple Tests for Identifying Meteorites
1. Magnet Test
Use a strong magnet:
- Strong attraction = possible meteorite
- Weak or no attraction = likely terrestrial
2. Streak Test
Rub the specimen on unglazed tile:
- Meteorites usually leave no streak or a very faint gray streak.
- Red, brown, or earthy streaks indicate an Earth rock (often hematite).
3. Nickel Test
Meteorites contain nickel, which is rare in common Earth rocks.
A chemical nickel test kit can confirm its presence.
4. Density Test
Weigh and measure the volume of your rock:
- Meteorites are denser than typical volcanic or sedimentary rocks.
5. Examination Under Magnification
Look for:
- metal grains
- chondrules
- uniform texture
Earth rocks often have varied crystal sizes or quartz inclusions.
Common Meteor-wrongs (Look-alikes)
1. Slag
Industrial byproducts such as furnace slag can look metallic and heavy.
- Full of bubbles or cavities
- Often very lightweight for its size
2. Hematite & Magnetite
Metallic luster and magnetism can mislead beginners.
- Streak test is the key: hematite leaves a red streak.
3. Basalt
Dark volcanic rock but:
- Low density
- Often contains vesicles (air pockets)
Meteorites rarely have holes.
4. Pseudometeorites
Weathered Earth rocks with fusion crust–like features mislead many collectors, but careful testing reveals differences.
Where Meteorites Are Most Commonly Found
You can find meteorites anywhere, but ideal locations include:
- Deserts (dry, stable conditions preserve dark meteorites)
- Flat plains
- Ice-covered areas (Antarctica is the world’s largest meteorite collector)
- Open fields where dark rocks stand out against light ground
When to Get Professional Verification
If your specimen matches several meteorite characteristics, consider contacting:
- A university geology department
- A natural history museum
- A certified meteorite lab
They can perform advanced tests such as:
- X-ray fluorescence (XRF)
- Electron microprobe analysis
- Isotopic analysis
Final Tips for Rockhounds
- Use multiple tests—never rely on just one clue.
- Study verified meteorites to train your eye.
- Document the area where you found the rock; provenance matters.
- Handle potential meteorites carefully to avoid altering the crust or interior.
Copyright
© Gems and Minerals Rock. All rights reserved.
About The Author
