Blue John

Blue John is a rare form of a semiprecious stone that is only known to be found at a hillside in the vicinity of Mam Tor, near Castleton, in the Derbyshire Peak District National Park, England. The name Blue John originated from the French term, ’Bleu Jaune’, that literally means Blue Yellow. Chemically a form of fluorite, it was discovered when miners were exploring the cave systems of Castleton for lead. Its unique properties make it ideal for making jewellery. An industry dedicated to mining and making of Blue John articles was soon established.

Blue John is commonly referred to as fluor spar by the old miners. Fluorite is popularly used in toothpastes; however, the form of fluorite found in Castleton is banded in shades of purple, yellow or grey. There are about 14 categories for banding Blue John patterns.

Since its discovery, huge quantities of the mineral have been mined from the Blue John mine. Since 1750, the Blue John stone has been used to make different kind of ornaments. A wide range of jewellery items are made from this mineral, like brooches, pendants, etc. Today, there are only a few Blue John industries; however, many shops at Castleton still sell locally-made articles of Blue John.

There are several online stores that provide hand crafted Blue John jewellery like Blue John brooches and Blue John pendants. Many online sites also offer detailed information about this mineral.