Feldspar
Feldspar is a family of pale silicate minerals rich in aluminium, and the commonest mineral group in Earth's crust.
Feldspars are a family of minerals made of aluminium, silicon and oxygen together with calcium, sodium or potassium. They are usually white, cream, grey or pink, and they make up more than half of Earth's crust.
In meteorites the main feldspar is plagioclase, the calcium and sodium kind. It is the pale mineral in eucrites, giving these Vesta rocks their speckled grey and white look, and it forms the bright highland rocks of the Moon. Potassium feldspar is much rarer in meteorites, because most of their parent bodies were short of potassium.
In many shocked meteorites the feldspar has been squeezed so hard that it turned to glass without melting, forming maskelynite. In chondrites, the amount and size of feldspar grains increases with heating, so feldspar is a quiet record of what happened inside the parent asteroid. With a hand lens, it shows as white or clear patches between darker grains.
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Level: Beginner Ages 7 and up