Mud Bricks

Mud Bricks are a decorative block obtained by crafting 4 packed mud.

Breaking
Mud Bricks can be broken by hand, but using a pickaxe speeds up the process. It drops itself even when broke by hand.

Note Blocks
Mud Bricks can be placed under note blocks to produce "bass drum" sounds.

Trivia

 * In real life, mudbricks are made with mud mixed together with straw, and then heated to increase their toughness. They have a long history of being used as building materials, dating back at least 5,000 years.