The area around Modum in the Norwegian province of Buskerud was one of Europe’s principal sources of cobalt. The ore was discovered in 1772 by Ole Witloch, and in 1776 a royal decree established the Blaafarveværket (blue colouring works) which for many years was under German management and was in German ownership from 1822. The colouring was a mixture of potassium carbonate, quartz and cobalt oxide which was poured into water. The crystals that formed by precipitation were ground into powder by quartzite millstones. The powder was used in the manufacture of paint, ceramics and glass. Arsenic and sulphur compounds were removed from the ore in calcining kilns, and some of the arsenic compounds were sold as by-products. In the mid-nineteenth century some 500 people were employed at the Blaafarveværket, making it the largest industrial concern in Norway, but production of colourings ceased in 1855 after the discovery of ultramarine which displaced cobalt in paints. Mining continued until 1898.
A foundation was formed in 1971 to conserve the remaining buildings, and its status was formalised under current museums legislation in 2004. The Blaafarveværket in the village of Åmot now houses an art gallery and visitor centre, with shops and restaurants on other parts of the premises. Visitors are able to tour the mine, 8 km. from the Blaafarveværket, together with Nyfossum, the home of the technical director, and Nymoen No 9, a typical worker’s home. Other buildings have been adapted as restaurants, shops and art galleries.