Blocky aerinite criptocristalline with fragments of dolerite included. Excellent color. Aerinite was used as a blue pigment in many Romanesque paintings in the Pyrenees between the 11th and 14th centuries. Its characteristic blue color varies from dark to pale blue. In fact, its name comes from a Greek root aerinos meaning "atmosphere" or "sky", as it was only known by that color. Obtaining these specimens of pure aerinite nowadays is almost impossible.