When identifying a meteorite, several key features can help distinguish it from terrestrial rocks.
First, examine the exterior for a fusion crust, a thin, dark, glassy layer formed as the meteorite burns through Earth's atmosphere. This crust is often black or dark brown and may appear shiny or matte.
Next, look for regmaglypts, which are thumbprint-like indentations on the surface, caused by ablation during atmospheric entry.
Magnetic properties are another indicator; most meteorites contain iron-nickel metal, making them attract magnets. However, not all meteorites are strongly magnetic, so this should not be the sole criterion.
Density is also a factor; meteorites are generally denser than Earth rocks due to their metal content.
Chondrules, small, round particles found in chondritic meteorites, are a distinctive feature. These are not present in terrestrial rocks and can be observed in a cut or broken section of the meteorite.
Additionally, examine the interior for a metallic luster or a speckled appearance, indicating the presence of metal grains.
Streak tests can be useful; meteorites typically leave a gray or black streak, unlike the reddish streak of hematite or the brown streak of limonite.
Lastly, consider the location and context of the find. Meteorites are more likely to be found in deserts or ice fields, where they stand out against the landscape.
For a definitive identification, laboratory analysis is recommended. Techniques such as X-ray fluorescence (XRF) or scanning electron microscopy (SEM) can confirm the presence of extraterrestrial minerals and isotopic compositions.
Consulting academic sources like university earth and planetary science publications or professional organizations can provide further guidance and validation.
