Bath Stone is an oolitic limestone comprising granular fragments of calcium carbonate. Originally obtained from the Combe Down and Bathampton Down Mines under Combe Down, Somerset, England. Its honey colouring gives the World Heritage City of Bath, England its distinctive appearance. An important feature of Bath Stone is that it is a 'freestone', so-called because it can be sawn or 'squared up' in any direction, unlike other rocks such as slate, which form distinct layers. Some quarries are still in use, but the majority have been converted to other purposes or are being filled in.