Lapis lazuli, gem with a long tradition

Lapis lazuli, also referred to as lapis, is a stone with one of the longest traditions of being considered a gem. Deep blue in color and opaque, it was regarded as a stone fit for royalty and fetched a princely sum. It takes a prominent place in many treasures recovered from the tombs of the pharaohs of ancient Egypt.

Lapis has been used to produce jewelry, carvings, mosaics, and a variety of ornamental pieces. In addition, prior to the discovery and chemical synthesis of various blue pigments, the stone was ground and processed to produce ultramarine, a pigment used in tempera paints. In architecture, the pigment has been used to clad the walls of palaces and shrines. The popularity of lapis as a gemstone continues through today.

Taken as a whole, lapis lazuli means “stone of azure.” The first part of the name is the Latin lapis, meaning stone. The second part, lazuli, is the genitive form of the medieval Latin lazulum, which came from Arabic (al-)lazward, which came from Persian lāzhward. This was originally the name of a place, but it soon came to mean blue because of its association with the stone. The English word azure, the Spanish and Portuguese azul, and the Italian azzurro are cognates.

Lapis lazuli usually occurs in crystalline marble as a result of contact metamorphism. The finest lapis comes from the Badakhshan area in northern Afghanistan. This source may be the world’s oldest continually worked set of mines for lapis—the same mines operating today supplied lapis to the pharaohs and ancient Sumerians. Using stones from this source, the artisans of the Indus Valley Civilization made beautiful carvings and merchants traded them in distant lands.

In addition to the Afghan deposits, lapis has been found in the Andes near Ovalle, Chile, where it is usually pale blue rather than deep blue. Other less important sources are the Lake Baikal region of Russia, Siberia, Angola, Burma, Pakistan, United States (California and Colorado), Canada, and India.

The finest color is intense blue, lightly dusted with small flecks of golden pyrite. There should be no white calcite veins, and the pyrite inclusions should be small. Stones that contain too much calcite or pyrite are not as valuable. Patches of pyrite are an important help in identifying the stone as genuine and do not detract from its value. Often, inferior stones are dyed to improve their color, but these are often a very dark blue with a noticeable gray cast.

Lapis takes an excellent polish and has been made into jewelry, carvings, boxes, mosaics, ornaments, and vases. In architecture, it has been used for cladding the walls and columns of churches and palaces.

It was also ground to a powder, processed to remove impurities, and lazurite was isolated to prepare the pigment ultramarine. This pigment was used for tempera paint and, more rarely, oil paint. Its usage as a pigment in oil paint nearly ended in the early nineteenth century, as a chemically identical synthetic variety, often called French ultramarine, became available.

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