Terracotta, a clay-based and unglazed ceramic, is a common type of earthenware.
Earthenware is pottery that has not been fired to vitrification, which is the process of crystalline silicate compounds bonding into noncrystalline glass compounds. This makes the pottery more porous and coarser to the touch. Earthenware pottery was the most common type of ceramics until the 18th century. Terracotta, a clay-based and unglazed ceramic, is a common type of earthenware. Today, we commonly see planters made from terracotta, along with bricks, water pipes, and more.