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Lapis Lazuli Options
Daemon
Posted: Wednesday, September 20, 2017 12:00:00 AM
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Lapis Lazuli

Lapis lazuli is a semiprecious stone prized since antiquity for its intense blue color. It has been mined in Afghanistan for 6,500 years, and the discovery of artifacts at several Predynastic Egyptian and Neolithic sites indicates widespread early trade in the stone. Powdered lapis was used until the 19th century to make blue pigment and may have even been used as eye shadow by Cleopatra. Today, much of what is sold as lapis lazuli is actually dyed jasper. Where does lapis lazuli get its name? More...
ChristopherJohnson
Posted: Wednesday, September 20, 2017 9:24:13 AM

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There are several Egyptian artifacts made from this mineral.
raghd muhi al-deen
Posted: Wednesday, September 20, 2017 9:41:37 AM

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lapis lazuli
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"Lapis" redirects here. For other uses, see Lapis (disambiguation).
Lapis lazuli
Lapis-lazuli hg.jpg
Lapis lazuli from Afghanistan in its natural state
General
Category Metamorphic rock
Formula
(repeating unit) mixture of minerals with lazurite as the main constituent.
Crystal system None, as lapis is a rock. Lazurite, the main constituent, frequently occurs as dodecahedra
Identification
Color Blue, mottled with white calcite and brassy pyrite
Crystal habit Compact, massive
Fracture Uneven-Conchoidal
Mohs scale hardness 5–5.5
Luster dull
Streak light blue
Specific gravity 2.7–2.9
Refractive index 1.5
Other characteristics The variations in composition cause a wide variation in the above values.
Lapis lazuli (/ˈlæpɪs ˈlæzjuːli/, /-ˈlæzjuːlaɪ/), or lapis for short, is a deep blue metamorphic rock used as a semi-precious stone that has been prized since antiquity for its intense color. As early as the 7th millennium BC, lapis lazuli was mined in the Sar-i Sang mines,[1] in Shortugai, and in other mines in Badakhshan province in northeast Afghanistan.[2] Lapis was highly valued by the Indus Valley Civilisation (3300–1900 BC). Lapis beads have been found at Neolithic burials in Mehrgarh, the Caucasus, and even as far from Afghanistan as Mauritania.[3] It was used in the funeral mask of Tutankhamun (1341–1323 BC).[4]
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 some of the most important artists of the Renaissance and Baroque, including Masaccio, Perugino, Titian and Vermeer, and was often reserved for the clothing of the central figures of their paintings, especially the Virgin Mary.
Today, mines in northeast Afghanistan and Pakistan 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.[5]
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 لاجورد lājaward, itself from the Persian لاجورد lājavard, which is the name of the stone in Persian[6] and also of a place where lapis lazuli was mined.[7][8]
The name "Lapis lazuli" came to be associated with its color. The English word azure, French azur, Italian azzurro, Polish lazur, Romanian azur and azuriu, Portuguese and Spanish azul, and Hungarian azúr all come from the name and color of lapis lazuli.
Science and uses


A sample from the Sar-i Sang mine in Afghanistan, where lapis lazuli has been mined since the 7th Millennium BC.


A polished block of lapis lazuli


Natural ultramarine pigment made from ground lapis lazuli. This was the most expensive blue pigment during the Renaissance, often reserved for depicting the robes of Angels or the Virgin Mary.
Composition
The most important mineral component of lapis lazuli is lazurite[9] (25% to 40%), a feldspathoid silicate mineral with the formula (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2.[10] Most lapis lazuli also contains calcite (white), sodalite (blue), and pyrite (metallic yellow). Some samples of lapis lazuli contain augite; diopside; enstatite; mica; hauynite; hornblende, nosean, and sulfur-rich löllingite 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 trisulfur (S
3) radical anion in the crystal.[11] An electronic excitation of one electron from the highest doubly filled molecular orbital (No. 24) into the lowest singly occupied orbital (No. 25)[12] 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.[13] Afghanistan was the source of lapis for the ancient Egyptian and Mesopotamian civilizations, as well as the later Greeks and Romans. Ancient Egyptians obtained this material through trade from Afghanistan. During the height of the Indus Valley Civilisation about 2000 BC, the Harappan colony now known as Shortugai was established near the lapis mines.[3]
According to the Sorbonne's mineralogist Pierre Bariand's leading work on the sources of lapis lazuli in modern times, and to references in Afghanistan's Blue Treasure: Lapis Lazuli (2011) by Lailee McNair Bakhtiar, the lapis lazuli is found in "caves" not traditionally considered "mines" and the stone lapis lazuli is from the primary source of the Hindu Kush Mountains in Afghanistan's Kochka River Valley and not in Pakistan.
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 in Angola; Argentina; Burma; Pakistan; Canada; Italy, India; and in the United States in California and Colorado.[5]
Uses and substitutes
Lapis takes an excellent polish and can be made into jewelry, carvings, boxes, mosaics, ornaments, small statues, and vases. During the Renaissance, Lapis was ground and processed to make the pigment ultramarine for use 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.
Lapis lazuli is commercially synthesized or simulated by the Gilson process, which is used to make artificial ultramarine and hydrous zinc phosphates.[14] It may also be substituted by spinel or sodalite, or by dyed jasper or howlite.[15]

with my pleasure
monamagda
Posted: Wednesday, September 20, 2017 11:13:52 AM

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This historical stone has a name closely associated with its intense color. Its name was derived from the Latin word 'lapis' meaning 'stone', and from the Arabic and Persian word 'lazaward'. 'Lazaward" was the Persian name for lapis stone, as well as the name of its mining location. In other parts of the world, words for 'blue' were named after the color of lapis, including the English word 'azure'; Italian 'azzurro'; Polish 'azur'; Spanish 'azur' and Romanian 'azuriu'. Today, lapis lazuli is still considered to be one of the most important opaque blue gemstones available.


https://www.gemselect.com/gem-info/lapis-lazuli/lapis-lazuli-info.php


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