Cotswold stone is a type of limestone that has been used for centuries to build houses, churches, bridges, and walls in the Cotswolds region of England. It is one of the most distinctive features of this area, giving it a warm and charming character.
But what makes Cotswold stone so special? And how did it get its unique color?
In part 1 of this series, we'll go back in time to explore the origins and evolution of this remarkable material.
The Origins of Cotswold Stone
Cotswold stone was formed about 180 million years ago during the Jurassic period when much of England was covered by a shallow tropical sea. The sea was teeming with life forms such as corals, mollusks, sea urchins, and algae. These organisms secreted calcium carbonate shells or skeletons that accumulated on the sea floor over millions of years.
As more layers of sediment were deposited on top of these shells, they were compressed and cemented together by water and minerals. This process created a type of rock called oolitic limestone (from the Greek word for "egg"), which consists of tiny spherical grains called ooids.
Ooids are formed when calcium carbonate crystals grow around a nucleus, such as a sand grain or a shell fragment. They have concentric layers like an onion or a pearl. Oolitic limestone is rich in fossils, especially those of sea urchins (echinoids), which give it a distinctive texture and pattern.
In part #2 of this series, we’ll look at the color of the Cotswold Stone.