Marble countertops come in a vast array of colors and shades. A marble countertop usually has a base color and is stained with other colors in irregular patterns, to create a natural look.
In its natural form, marble is completely white. The white comes from the high concentration of calcium in the marble. Marble is a metamorphic rock, and is created when limestone is subjected to extremely high pressures and temperatures within the Earth's crust. If the limestone is pure and kept away from other substances, the resulting marble will be a milky, translucent white. This is the rarest and most valued variety of marble, and is often used for sculptures and statues. Mineral deposits, chemicals, and gases may cause discolorations in the white marble, resulting in such shades as cream, beige, gray, red or green.
Cream marble is colored with sand and is usually found near deposits of sandstone. The naturally brownish tone of the sand mixes with the white of the calcium, producing a lush cream color. Cream marble is also valued for the swirls and intricate designs commonly found in it. The patterns usually look like gently curved lines, which are actually internal cracks caused by the extreme pressure than the marble sustains during formation.
Gray marble can come from coal mines or from a combination of white marble and chert, a gray-blue sedimentary rock found in the Earth's crust. Marble deposits found near coal mines get their gray color from the carbon content of the coal. Generally, the closer the marble is to a coal deposit, the darker the stain is. Some marble samples found right alongside coal is almost black, and fades to progressively lighter shades of gray as one moves away from the coal. Gray marble can also be created by the synthesis of white marble and chert. Such marble varieties are much lighter than carbon-stained marble. When viewed under intense light, chert-stained marble can have a bluish tint.
Iron ore deposits have a natural deep reddish tint can stain marble pale pink to deep red, depending on the concentration. Extreme pressure in the Earth's crust presses iron ores and calcium limestone together, forming marble stones with a wide gradient of colors. Multiple shades of red can often be found within a single marble sample. Every shade, from a blushing rose-like tint to wine-dark red, can be found in a single piece of marble.
Green marble is the result of the fusion between serpentine and marble stone. Serpentine is a magnesium-rich silicate with a slightly crystalline nature. Other compounds such as chromium, manganese, nickel and cobalt may be present in the serpentine's chemical mixture, resulting in a wide variety of greens which stains the marble. Green marble has a more crystalline look and is therefore more refractive, that is, more sparkly than other colors.