Lapis Lazuli

Lapis Lazuli Gemstones

• Hardness

  5.5.
  

• Occurrence

  Afghanistan, Russia, Chile and the U.S..
  

• Appearance

  Dark blue with metallic patches (pyrite) and/or white streaks (calcite). Lapis lazuli can be made of several minerals besides lazurite, namely sodalite, hauyne, calcite and pyrite. Stones that are deep blue with small patches of pyrite and calcite are considered the most valuable. Like turquoise, lapis lazuli is an opaque stone. It was believed by some that lapis lazuli would protect the wearer from evil.
  

• Enhancements

  Lapis lazuli is commonly impregnated with colorless wax or oil to improve appearance. Lapis lazuli is also commonly dyed to provide color and/or uniformity.
  More information on gemstone enhancements.
  
  

  Lapis Lazuli

  Lapis lazuli (sometimes abbreviated to lapis) is a deep blue semi-precious stone that has been prized since antiquity for its intense color.
  
  Lapis lazuli was being mined in the Sar-i Sang mines and in other mines in the Badakhshan province in northeast Afghanistan as early as the 7th millennium BC, Lapis beads have been found at neolithic burials in Mehrgarh, the Caucasus, and even as far from Afghanistan as Mauritania. It was used for the eyebrows on the funeral mask of King Tutankhamun (1341–1323 BC).
  
  At the end of the Middle Ages, lapis lazuli began to be exported to Europe, where it was ground into powder and made into ultramarine, the finest and most expensive of all blue pigments. It was used by the most important artists of the Renaissance and Baroque, including Massaccio, Perugino, Titian and Vermeer, and was often reserved for the clothing of the central figure of the painting, especially the Virgin Mary.
  
  Today mines in northeast Afghanistan are still the major source of lapis lazuli. Important amounts are also produced from mines west of Lake Baikal in Russia, and in the Andes mountains in Chile. Smaller quantities are mined in Italy, Mongolia, the United States and Canada.
  
  

  Etymology

  
  Lapis is the Latin word for "stone" and lazuli is the genitive form of the Medieval Latin lazulum, which is taken from the Arabic lāzaward, itself from the Persian lāžaward, which is the name of the stone in Persian and also of a place where lapis lazuli was mined.
  
  The name of the stone came to be associated with its color. The English word azure, French azur, the Italian azzurro, the Polish lazur, Romanian azur and azuriu, and the Portuguese and Spanish azul, Hungarian azúr all come from the name and color of lapis lazuli.
  
  
  

  Composition

  
  Lapis lazuli is a rock whose most important mineral component is lazurite (25% to 40%), a feldspathoid silicate mineral with the formula (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2. Most lapis lazuli also contains calcite (white), sodalite (blue), and pyrite (metallic yellow). Other possible constituents: augite; diopside; enstatite; mica; hauynite; hornblende, and nosean. Some lapis lazuli contains trace amounts of the sulfur-rich löllingite variety geyerite.
  
  Lapis lazuli usually occurs in crystalline marble as a result of contact metamorphism.
  
  

  Color

  
  The intense blue color is due to the presence of the S3- radical anion in the crystal. An electronic excitation of one electron from the highest doubly filled molecular orbital (No. 24) into the lowest singly occupied orbital (No. 25) results in a very intense absorption line at λmax ~617 nm.
  

   

  Sources

  
  Lapis lazuli is found in limestone in the Kokcha River valley of Badakhshan province in northeastern Afghanistan, where the Sar-e-Sang mine deposits have been worked for more than 6,000 years. Afghanistan was the source of lapis for the ancient Egyptian and Mesopotamian civilizations, as well as the later Greeks and Romans. During the height of the Indus valley civilization about 2000 BC, the Harappan colony now known as Shortugai was established near the lapis mines.
  
  In addition to the Afghan deposits, lapis is also extracted in the Andes (near Ovalle, Chile); and to the west of Lake Baikal in Siberia, Russia, at the Tultui Lazurite deposit). It is mined in smaller amounts Angola; Argentina; Burma; Pakistan; Canada; Italy, India; and in the USA in California and Colorado.
  

   

  Alternatives

  
  Lapis lazuli is commercially synthesized or simulated by the Gilson process, which is used to make artificial ultramarine and hydrous zinc phosphates.It may also be substituted by spinel or sodalite, or by dyed jasper or howlite.
  

   

  Uses

  
  Lapis takes an excellent polish and can be made into jewelry, carvings, boxes, mosaics, ornaments, and vases. It was also ground and processed to make the pigment ultramarine, widely used during the Renaissance in frescoes and oil painting. Its usage as a pigment in oil paint largely ended in the early 19th century when a chemically identical synthetic variety became available .