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 ...

There are over 5,000 known types of minerals. Just a few minerals make up most of the rocks we see, though: feldspars, amphiboles, quartz, olivine, garnet, micas, calcite, and pyroxenes.

The chemistry of the rock layers reveals remnants of the meteor itself, which was a primitive type of space rock called a ...