Northwich evidence of a Roman auxiliary fort within the area of Northwich now known as "Castle" dated to AD 70. This and other northwestern forts were built as the Romans moved north from their stronghold in Chester. The association with salt continues in the etymology of Northwich. The "wich" (or wych) suffix applies to other towns in the area: Middlewich, Nantwich and Leftwich. This is considered to have been derived from the Norse, "wic", for bay, and is associated with the more traditional method of obtaining salt by evaporating sea water. Therefore, a place for making salt became a wych-house; Northwich
Blue John (mineral) Blue John (mineral) Blue John (also known as Derbyshire Spar) is a semi-precious mineral, a form of fluorite with bands of a purple-blue or yellowish colour. In the UK it is found only at Blue John Cavern and Treak Cliff Cavern at Castleton in Derbyshire. During the 19th century, it was mined for its ornamental value, and mining continues on a small scale. Deposits of fluorite have been recently found in China with colouring and banding similar to the classic Blue John stone. The most common explanation for the name is that it derives from the French "bleu-jaune", meaning 'blue-yellow'.