True blue, royal blue, ultramarine: During the Renaissance, these were all names for the most prized of all pigments, lazurite, derived from the semiprecious mineral lapis lazuli. Mined and processed since the sixth century almost exclusively in Afghanistan, and imported to European markets through Venice, it was worth more than five times its weight in gold. It was used sparingly, often reserved for the richest patrons by the most prosperous artists.