Fireclay is a clay based material that is coated with a special heavy glaze. The sink is placed in a kiln and fired at a very high temperature, 1800 degrees plus! This creates a durable and non-porous bond, making it ideal for sinks.
A fireclay sink can be used in most any kitchen style but more often seen in a farmhouse or apron sink style, which is extremely popular.
The cost for a fireclay sink is more due to the added process but may be well worth the investment depending on your budget and the environment your wanting to create.