Marble is a metamorphic rock found in the mountainous regions of most countries of the world. Marble quarried in India, China, Italy, and Spain represents the majority of marble, in terms of volume, that is utilized worldwide. Because of its beauty and elegance, marble is a popular choice for countertops, floors, foyers, fireplace facings and hearths, walls, and windowsills. Marble, with its inherent warmth, adds a sophisticated element to the area in which it is installed. Its naturally random appearance, engineering characteristics, and ease of maintenance makes it a premium choice for floors, wall claddings, table tops, wainscot, floors, and vanity tops. Many marbles are well suited for wet area application, which extends the versatility of this material to include tub decks and showers. The calcite crystal is the basic building block of true marbles. The calcite crystal is vulnerable to attack by mild acids, including those commonly found in kitchen and bar settings. The user selecting marble for these applications should be aware of, and accepting of the maintenance and patina that is to be anticipated with this combination. Acid rain and other weathering elements can also affect exterior marble installations, and exterior applications are generally limited to white marbles, with some exceptions.