Ultramarine is a blue pigment that has a reddish hue. It is used in materials such as paints, inks, and paper products. Workers prepare ultramarine by heating various combinations of China clay, sodium carbonate, carbon, and sodium sulfate until they form a powder. People once ground ultramarine from the rare mineral lapis lazuli. This method produced a brilliant, durable blue color, which was prized by artists, but was very expensive. See also Lapis lazuli.
