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 ...

However, they do not reveal the relative ages of rocks preserved in two different areas. In this case, fossils can be useful tools for understanding the relative ages of rocks. Each fossil species ...

Large crystals found in geodes and other rocks are relatively ... Chalcedonies include many types of cryptocrystalline quartz gems and feature a number of different colors. Geologists can tell ...

In the experiment, the team introduced new types of rock to the animals ... “We measured rocks using three different standard ...