Onyx is a translucent material that is formed from stalactites and stalagmites in caves. Onyx comes in a variety of different colors and is softer than most marbles, Because of it’s translucent characteristic, onyx is a great material for underlet countertops, such as wet bars and powder baths. Onyx is not recommended for kitchens or heavily used areas, but it has the same care and maintenance as marble. Onyx comes in two different finishes honed and polished, and please see the Marble section for more information.