It depends on what the rocks are made of – and that’s related to how they were formed. There are three main rock types: ...

Sometimes scientists must dig and work and sweat to make scientific discoveries. And sometimes a robot rolls over a rock that turns out to be a revelation. That's what happened when Mars ...

Metamorphic rocks are also formed because of change in their environment - they are created by great heat or pressure transforming other rock types. For instance, hot, molten lava underground can ...