Dolomite is a sedimentary rock composed primarily of the mineral dolomite. It is formed by the post depositional alteration of lime mud and limestone by magnesium-rich groundwater. Dolomite, like most natural stones is porous and needs to be sealed to prevent staining. Although it is more durable than true marble, it can etch when exposed to strong acids or alkaline solutions so be aware of the maintenance concerns before using in a kitchen.