Cobblestone

Cobblestone is a very common block and is used in lots of recipes.

Natural Occurrence
Cobblestone naturally generates when lava touches water.

Mining
Cobblestone is mined from stone, which is found underground in huge quantities

Generator
See Tutorials/Cobblestone Generator

Uses
Cobblestone is used to make cobblestone generators and is used in a lot of recipes. It is also used to make medieval houses and castles. It is a very common building material, since the mining of stone drops cobblestone.