Terracotta

Hardened clay currently has few known uses other than an aesthetic block with the same explosion resistance as stone-related blocks. It is somewhat of a cross between clay and bricks and can be obtained by smelting clay.

Behavior
Hardened clay has an above-average resistance towards explosions. Unlike normal clay, a wall of 4 hardened clay blocks thick can withstand a direct TNT or creeper explosion while only one column would be destroyed.

As of snapshot 13w19a, hardened clay could be colored with dies to create stained hardened clay. All colors of hardened clay are currently available.

Trivia

 * Hardened clay was suggested by BlameTC.