Hearthstones, also known as firestones, are the stones used in a fireplace or hearth. A few synonyms for the word "hearthstones" include uncut stone, cobblestone, flagstone, paver, and slate. Cobblestones were traditionally used in streets and are made of rustic and irregularly shaped stones, while flagstones are flat stones used in a variety of outdoor applications, including walkways and patios. Pavers are man-made stones often used for outdoor spaces and come in a wide range of colors, shapes, and sizes. Slate, on the other hand, is a natural stone that is popular for indoor and outdoor spaces, including roofs, floors, and walls.