How do scientists cut and study a meteorite?
They cut meteorites with diamond saws, prepare polished slices and thin sections, and analyse them with microscopes, electron beams and mass spectrometers, often using only tiny amounts.
Studying a meteorite starts with a careful plan, because samples are precious and some analyses destroy material.
Cutting. Meteorites are usually cut with saws edged with diamond, lubricated with oil or water-free fluids for sensitive samples, to avoid rust or contamination. Some carbonaceous chondrites are prepared in clean rooms or dry nitrogen cabinets, and some sample sections are cut without any liquid.
Polished sections. A cut face is ground smooth and polished with progressively finer abrasives until it shines like a mirror. Polished slabs show textures such as chondrules, metal and Widmanstätten patterns.
Thin sections. A slice is glued to a glass slide and ground to about 30 micrometres thick, thin enough for light to pass through most minerals. Under a polarising microscope, minerals show characteristic colours and patterns, allowing identification and classification.
Electron instruments. A scanning electron microscope reveals fine textures, and an electron microprobe measures the chemical composition of spots a few micrometres across.
Isotope measurements. Mass spectrometers measure isotopes for dating and fingerprinting. Ion probes analyse isotopes in tiny spots without dissolving the sample.
Other techniques. X-ray computed tomography scans the inside of whole meteorites without cutting them, revealing chondrules, metal and fractures in three dimensions. Spectroscopy, X-ray diffraction and chromatography identify minerals and organic compounds.
Scientists share material, so a single meteorite can be studied by many laboratories worldwide. Detailed records ensure that each piece's history, from the field to the laboratory, is known.