Stone

**What are stones?** Stones are minerals that are made of rock. 

I know just a few kinds of stone, like granite, limestone or marble.
 * How many kinds of stone do you know?**

Stones are solid and hard and are usually grey or brown, but can be any color.  Because there are a very solid and durable material.
 * What characteristics do stones have?**
 * Why are stones used in construction?**