Lapis lazuli: the blue that built an empire of colour
For thousands of years this rock was the only source of a true deep blue, and it was worth more than gold.
Lapis lazuli is a rock, not a single mineral. Its blue comes from lazurite, a sodium calcium aluminium silicate with sulphur. Mixed in are white streaks of calcite, small gold flecks of pyrite, and smaller amounts of other minerals such as diopside and sodalite. The best lapis is an even deep blue with a light dusting of pyrite and little calcite.
People have mined lapis in the mountains of Badakhshan, in what is now Afghanistan, for more than 6,000 years. It was carved into beads and seals in Mesopotamia and set into the gold mask of Tutankhamun. Its name joins the Latin "lapis", stone, with a Persian word for blue.
Ground to powder and refined, lapis made ultramarine, the most expensive pigment of the Renaissance. Painters saved it for the robes of the Virgin Mary because it cost more than gold. A synthetic ultramarine was invented in the 1820s, and the price of blue fell overnight.
Lapis is softer than quartz, at about 5 to 5.5 on the Mohs scale, and its calcite and pyrite are softer still. That is why it takes a beautiful polish but should be stored apart from harder stones, kept out of acids and dried quickly after washing.
Renaissance painters paid more for lapis blue than for gold.




