Portland stone is a type of limestone that is quarried on the Isle of Portland in Dorset, England. It is known for its light color, typically ranging from white to light grey, and its fine grain. This stone has been used in many notable buildings, including St. Paul's Cathedral in London, due to its durability and aesthetic appeal. The stone is formed from marine fossils and is approximately 150 million years old. Its unique properties make it suitable for both construction and sculpture. Portland stone is often used for facades, monuments, and decorative elements in architecture.