Cobblestone is a common block, used for creating various items, that resembles an uneven, roughly paved surface. Cobblestone only occurs naturally in dungeons, NPC Villages, strongholds, or when water and flowing lava come into contact (which allows for infinite cobblestone generators to be made). However, if the lava flows on top of the water from above, stone will be created instead. It is commonly used to create walls for constructions with a medieval appearance such as castles, towers and roads. Cobblestone is obtained by mining stone. Cobblestone takes slightly longer to mine than normal stone, and there is an alternative version of the block known as Moss Stone. Silverfish have the ability to enter and hide in cobblestone (along with clean stone and stone bricks).