Clay Ball

Clay is the item obtained from mining clay blocks. Clay blocks are usually found in groups in shallow water, and are best mined using shovels. Each clay block yields four clay balls. Clay deposits are most easily found in the water in swamp biomes, but also appear in rivers, and abundant deposits are to be found in oceans, though you might want some enchanted gear or an underwater base to excavate it.

Usage
Clay can be crafted back together to form clay blocks or baked in a furnace to create bricks. Bricks can then be crafted into brick blocks or flower pots. In version 1.6(+), Clay Blocks can be heated in a furnace to make hardened clay. Hardened clay can then be dyed with various dyes to create colored blocks of hardened clay.

History
Prior to Minecraft version Beta 1.8, clay was a rare luxury material. The Minecraft version Beta 1.8 update changed the rate of distribution, making it much more common.