Spread a cloth or plastic paint tarp over the floor around the base of the hearth to collect the removed tile.
Don work gloves and a pair of safety glasses. Begin the tile removal at the firebox edge of the hearth by placing the tip of a cold chisel against the edge at the base of a tile and striking the cold chisel with a hammer to break the tile loose.
Scrape loose the tile grout as you remove the hearth tiles, using a pry bar or scraper. You can use a hand brush and dustpan to clean up the tile and grout debris it accumulates. The tile mortar will be brittle and should scrape free of the hearth surface without much effort.