Mineral
A mineral is a natural solid with a fixed chemical recipe and an orderly inner arrangement of atoms.
A mineral is a naturally formed solid whose atoms are stacked in a regular, repeating pattern and whose chemistry stays within set limits. Quartz, salt and olivine are all minerals. A rock is different: it is a mixture of minerals, rather like a fruit cake is a mixture of ingredients.
Meteorites are made of minerals too, and most of them are the same ones found on Earth, such as olivine, pyroxene and feldspar. That tells us the planets and asteroids were built from the same raw materials. Many minerals, however, were first found in meteorites, because space rocks formed in conditions with very little oxygen or water, or were squeezed by violent impacts.
Scientists identify minerals by their colour, shape, hardness and, most reliably, by measuring their exact chemistry and crystal structure with instruments. Learning a handful of the common meteorite minerals is the first step to reading what a space rock has been through.
Related terms
Level: Beginner Ages 7 and up