Chondrule
A chondrule is a tiny round grain, often smaller than a grain of rice, that formed as a melted droplet in space before the planets existed.
Imagine a cloud of dust around the young Sun, about 4.6 billion years ago. Something, scientists are still debating exactly what, heated little clumps of that dust until they melted into droplets. The droplets cooled quickly into tiny stony balls. These balls are called chondrules (say "KON-drools"). Most are between about 0.1 and 2 millimetres across.
Chondrules matter because they are some of the oldest solid things in the Solar System. They got stuck together with dust to build rocky bodies called asteroids, and pieces of those asteroids sometimes fall to Earth. Meteorites packed with chondrules are called chondrites, and they are the most common meteorites of all. The Allende meteorite, which fell in Mexico in 1969, is full of beautiful chondrules.
To spot chondrules, look at a cut and polished meteorite slice with a magnifying glass. You may see small round or oval shapes, a bit like seeds in a slice of cake, sometimes a different colour from the rock around them. Always ask an adult to help, and never try to cut, break or grind a rock yourself.
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Level: Beginner Ages 7 and up