Phosphate
A phosphate is a mineral containing phosphorus bonded to oxygen, such as apatite and merrillite.
A phosphate mineral is one in which phosphorus is combined with oxygen, usually alongside calcium. Phosphorus is essential to life on Earth, appearing in DNA and bones, so scientists are interested in how it was delivered to the early planet.
In meteorites, phosphates such as apatite and merrillite are found in small amounts, typically less than one per cent of the rock. They often form when phosphorus that was originally dissolved in metal reacts with oxygen during heating. In iron meteorites, phosphorus instead stays in metal-rich form as the mineral schreibersite, a phosphide.
Though minor in quantity, phosphates are major in importance. They collect rare earth elements and radioactive uranium and thorium, so they can be dated. They also record water and chlorine contents of magmas. In the lab, phosphate grains glow distinctively under an electron beam, helping researchers find them in thin sections.
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Level: Explorer Ages 10 and up