Is kyanite an igneous rock or a sedimentary rock or a metamorphic rock?

Answer

Dear Harald,

Kyanite is actually none of the three. Kyanite is not a rock but a mineral, so rather a building block of a rock that is made up of one or more minerals.

Kyanite can be formed in metamorphic rocks (when formed deep in the earth’s crust under high pressure) and pegmatites (igneous rocks in which special minerals often occur). As these rocks erode and weather, kyanite can sometimes end up as loose grains in river sands and along coasts. These sands can then harden into sandstones, which is why the mineral kyanite is sometimes found in sedimentary rocks.

If you were to study geology later – but that will take many years, of course – you will be able to learn a lot more about the wonderful world of the formation of rocks and minerals.