Pyroxene
A family of common rock-forming minerals made of silicon and oxygen chains, important in almost all stony meteorites.
Pyroxenes are a large family of minerals found in nearly every stony meteorite. They are silicates, built from long single chains of silicon and oxygen linked together with metals such as magnesium, iron and calcium. Different mixes give different pyroxenes: enstatite is magnesium-rich, augite and diopside are calcium-rich, and pigeonite has a little calcium.
Pyroxenes are useful detectives. Their chemistry records how hot a rock got and how fast it cooled, and the amount of iron in them helps scientists classify chondrites. Different achondrites are almost defined by their pyroxene: diogenites, such as Tatahouine from Tunisia, are made mostly of orthopyroxene; eucrites contain pigeonite; and the Martian nakhlites, like Nakhla from Egypt, are rich in augite. Pyroxene is also what lets astronomers spot Vesta's basaltic surface from Earth, because it absorbs particular colours of infrared light.
Pyroxene crystals are usually green, brown or black and have two cleavages (directions in which they split) meeting at nearly right angles. In meteorites, grains are generally small and best seen under a hand lens or microscope in a cut, polished face.
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Level: Explorer Ages 10 and up