Lapis lazuli is a rock, a contact metamorphosed limestone that contains lazurite. It also contains PYRITE, which adds a golden-yellow sparkle, and CALCITE, which shows as white flecks. Other trace minerals can include HAÜYNE, SODALITE, DIOPSIDE, wollastonite, amphibole, feldspar, mica, APATITE, SPHENE, ZIRCON, and pyroxenes. The stone was once powdered and mixed with oil to produce the pigment ultramarine (literally, ‘beyond the sea’), which is seen in the beautiful blues of Renaissance paintings. Ultramarine has been made synthetically since 1828. Lapis is Latin for ‘stone’. The names of both lazuli and lazurite are derived from the Persian word lazhuward and Latin word lazulum that means ‘blue’ or ‘heaven’. The lapis-lazuli name, often shortened to lapis, is sometimes mistakenly used for the mineral lazurite.
Lapis lazuli was mentioned in 2650 BC in the Sumerian epic of Gilgamesh. The ancient Egyptians used it extensively in religious ceremonies, and lapis items were found in the tomb of Tutankhamen. It was a popular stone in Mesopotamia, Persia, and the ancient city of Ur, which had a large trade in lapis lazuli. The Greeks and Romans used it as a reward for bravery. The ancients also employed it for inlaid work and for jewellery, amulets, and talismans. They named it sapphirus (‘blue’), which is now used for the blue corundum variety of SAPPHIRES. Lapis lazuli is mentioned in the Biblical book of Exodus. In the 17th century, it was used in medicine to prevent miscarriages, epilepsy, and dementia.
The value of lapis lazuli is largely determined by the abundance and colour of the dark intense blue lazurite. The colours range from greenish-blue to purple-blue. The flecks of gold pyrite and white calcite can often increase the value or, when too numerous or too large, decrease it. Lapis lazuli is cut and polished to make gemstones for jewellery and is also used as a decorative stone. Because it is slightly soft, it is normally cut as cabochons, and also used for beads, inlay material, and small carved items. The opaque mineral takes a good polish but may lose its lustre because of its softness. A Gilson laboratory imitation was produced in the mid 1970s but it is more porous. Other imitations are made using the gem JASPER artificially stained blue, known as ‘Swiss lapis’, and synthetic SPINEL coloured blue by cobalt.
Lapis lazuli usually occurs in crystalline limestone and is formed in contact metamorphic rocks associated with pyrite and calcite. It normally appears in massive and compact forms or as fine, granular aggregates. The best lapis lazuli is found in limestone in the Kokcha river valley of Badakhshan province in northeastern Afghanistan, and these deposits in the mines of Sar-e-Sang have been worked for more than 6,000 years. The Arab geographer Istakhri recorded a visit there in the 10th century, and Marco Polo visited and wrote about the lapis mines in c.1271.
Other occurrences include light blue boulders at the western end of Lake Baikal, southern Siberia, Russia; pale stones in the Andes, near Ovalle, central Chile; and a dark variety in the Rockies of Colorado, USA. It is also found in Italy, near Rome and on Monte Somma, Vesuvius. Other sources include Baffin Island, Nunavut, Canada, San Bernardino County, California and the Pamir Mountains of central Asia.
Related Credo Articles
Deep blue Metamorphic rock , found in crystalline Limestone and consisting of Lazurite mixed with other silicates, Calcite and Pyrite...
Lapis lazuli is not a single mineral but a rock consisting of blue lazurite with variable amounts of calcite and pyrite. The best, from Af
A blue semiprecious stone composed mainly of a sulphur-rich variety of the mineral haüyne (a feldspathoid) called lazurite. It is formed...