Cast iron fireplaces in the 1700s were quite ornate. These fireplace of the Georgian era were designed to be the focal point of the room.
They had intricate hand-carved designs. They were beautiful to look at but weren't very efficient in terms of providing warmth.
These fireplaces were quite fashionable. They had a built in wood burning grate.
Image source: Fire place Mt. A archives 7922/8/42