Stones

**Stones**
> Stones are made, in most of the cases, out of a mix of minerals that form a compact and solid material. They are also called rocks and since most of them were formed along with the earth itself, they may be found in every corner of the planet. > **
 * ** What are stones?

> I don't know many but in this moment I can name sandstone, pearls, diamonds, rubies, quartz, graphite and bauxite. > **
 * ** How many kinds of stone do you know?

> Stones are very compact and they are not flexible and most of them have a very hard consistency, but since there are many kinds of stones, we can recognize several differences between them, such as electric conductivity, solubility and hardness, because we can find, for example, bauxite which is a very hard and conductive stone, but we can also find graphite which is a very soft and bad conductive stone. > **
 * ** What characteristics do stones have?

> Stones are used in construction because of their strength and resistance, and because the majority of them doesn't yield against rain and water. They also protect people from environmental conditions which is one of the principal needs of buildings. **
 * ** Why are stones used in construction?