Crystallisation
Crystallisation is the growth of crystals from a melt, a gas or a solution, or within a solid as it is heated.
Crystallisation is the process by which atoms arrange themselves into crystals. It can happen when molten rock cools, when a hot gas condenses, when water evaporates and leaves dissolved minerals behind, or when a solid rock is heated enough for its atoms to reorganise.
All of these happened to meteorites. Chondrules crystallised from molten droplets within minutes to hours. Basaltic achondrites such as eucrites crystallised from lavas on Vesta. Iron meteorites crystallised as molten cores slowly froze. Carbonates and clays in carbonaceous chondrites crystallised from water inside asteroids.
The speed of crystallisation shapes the result. Rapid cooling gives tiny crystals or glass; slow cooling gives large, well-formed ones. The order in which minerals appear also matters, because each one removes certain elements from what is left. By reading crystal sizes, shapes and order, scientists reconstruct how a meteorite formed, much as a detective reads clues at a scene.
Related terms
Level: Explorer Ages 10 and up