How do crystals form in rocks?
Crystals form in rocks that have been heated to such a high degree deep within the earth that they actually melt. When these rocks cool down, crystals form.Molten RockCrystals in rock have usually been created millions of years ago when the rock was deep within the earth and was molten. As the rock cools down, the minerals within also cool down and become crystals.Chemical ShapeThere are many different types and shapes of crystals that form in rock. Fast moving atoms in molten rock gravitate toward each other and form crystalline shapes. A rock crystal gets its shape because of the mineral it is made out of.Glassy-LookingSometimes crystals in rock have no particular shape. This happens when melted rock cools down very quickly and the moving atoms in the rock have no time to form orderly patterns; then the crystal will be glassy-looking.Volcanic RockIf magma from a volcano cools slowly, large crystals are formed. If it is still hot when it reaches the Earth’s surface small crystals will