Named in 1881 in honour of the French palaeontologist Eugène Dumortier. An aluminium borosilicate mineral, formed under high-temperature, low-pressure metamorphic conditions.

Found in Brazil, Madagascar, Sri Lanka, and near Lyon in France. Long used as a raw material for ceramics—its resistance to heat made it well suited to firing.

Its history as a gemstone is brief, but its history as an industrial material is not. Before it was considered beautiful, it was considered useful. Its relationship with people began through function, not ornament.