There are lots of types of rock and each type has different properties and uses. For example, some are strong and hard but others are soft and sandy. Some rocks are harder than others. For example ...

Ever wonder how Earth scientists examine rocks? We cut them up and throw them under a microscope ... and then everything ...

Minerals are typically formed when molten rock, or magma ... Chalcedonies include many types of cryptocrystalline quartz gems and feature a number of different colors. Geologists can tell a ...