1. Why are the ferromagnesian silicates often dark, dense, and magnetic? 2. Why do rocks made from slowly cooling magma have large crystals? Give an example of this kind of rock. 3. How does the...

1. Why are the ferromagnesian silicates often dark, dense, and magnetic?

2. Why do rocks made from slowly cooling magma have large crystals? Give an example of this kind of rock.

3. How does the atomic structure of glass differ from the atomic structure of the mineral calcite?