Although it's acceptable to refer to your fireplace interchangeably as your hearth, the two differ significantly. In fact, a hearth is just one part of the larger fireplace.
Commonly referred to as a hearth, a fireplace is an opening at the base of a chimney in which you burn a controlled fire. You may add fireplaces to the interior or exterior of your home.
The floor on which you build fires is known as a hearth. The hearth often extends 1 to 4 feet outside of the fireplace opening. Hearths may set above, below or level with the floor in your home. Some hearths may even provide a bench-like seat in front of the fireplace or create a small ledge on which to display trophies and trinkets.
Hearths and other fireplace parts are commonly made from stone, brick or block because these materials resist cracking under heat and are not flammable. Poured-concrete hearths and concrete-block fireplaces can be covered with fire-resistant slate, tile or stone veneers. Outdoor fireplaces may have gravel or dirt hearths instead of brick, block or stone.