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Lapis lazuli



Lapis lazuli

polished specimen of Lapis lazuli
General
CategoryRock
Chemical formulamixture of minerals
Identification
ColorBlue, mottled with white calcite and brassy pyrite
Crystal habitCompact, massive
Crystal systemNone, as lapis is a rock. Lazurite, the main constituent, frequently occurs as dodecahedra
CleavageNone
FractureUneven-Conchoidal
Mohs Scale hardness5 - 5.5
Lusterdull
Refractive index1.5
Streaklight blue
Specific gravity2.7 - 2.9
Other CharacteristicsThe variations in composition cause a wide variation in the above values.

Lapis lazuli (sometimes abbreviated to lapis) is a semi-precious stone prized since antiquity for its intense blue color.

Lapis lazuli has been mined in the Badakhshan province of Afghanistan for 6,500 years, and trade in the stone is ancient enough for lapis jewelry to have been found at Predynastic Egyptian sites, and lapis beads at neolithic burials in Mehrgarh, the Caucasus, and even as far from Afghanistan as Mauritania.[1]

Additional recommended knowledge

Contents

Description

  Lapis is a rock, not a mineral, because it is made up from various other minerals. To be a mineral it can only have one constituent.[2]

The main component of lapis lazuli is lazurite (25% to 40%), a feldspathoid silicate mineral composed of sodium, aluminium, silicon, oxygen, sulfur, and chloride. Its formula is (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2.[3] Most lapis lazuli also contains calcite (white), sodalite (blue) and pyrite (metallic yellow). Other possible constituents are augite, diopside, enstatite, mica, hauynite, hornblende and nosean. Some contain trace amounts of the sulfur rich lollingite variety geyerite.

Lapis lazuli usually occurs in crystalline marble as a result of contact metamorphism.

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 lapis is dyed to improve its color, but this is often a very dark blue with a noticeable grey cast.

Uses

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

It was also ground and processed to make the pigment Ultramarine for tempera paint and, more rarely, oil paint. Its usage as a pigment in oil paint ended in the early 19th century as a chemically identical synthetic variety, often called French Ultramarine, became available.

Etymology

Lapis is the Latin for 'stone' and lazuli the genitive form of the Medieval Latin lazulum, which is from the Arabic lāzaward, which is ultimately from the Persian لاژورد lajward, the name of a place where lapis lazuli was mined.[4] The name of the place came to be associated with the stone mined there and eventually, with its colour. The English word azure, the Spanish and Portuguese azul, and the Italian azzurro are cognates. Taken as a whole, lapis lazuli means "stone of azure".

Sources

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.[5] Badakhshan was the source of lapis for the ancient Egyptian and Mesopotamian civilizations, as well as the later Greek and Roman; during the height of the Indus valley civilization about 2000 B.C., the Harappan colony now known as Shortugai was established near the lapis mines.[1]

More recently, during the 1980s conflict with the USSR, Afghanistan resistance fighters disassembled unexploded Soviet landmines and ordnance and used the scavenged explosive to help mine lapis to further fund their resistance efforts.[citation needed]

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

Cultural and historical/mythical usage

    

In ancient Egypt lapis lazuli was a favorite stone for amulets and ornaments such as scarabs; it was also used by the Assyrians and Babylonians for seals. Lapis jewelry has been found at excavations of the Predynastic Egyptian site Naqada (3300–3100 B.C.), and powdered lapis was used as eyeshadow by Cleopatra herself.[1]

As inscribed in the 140th chapter of the Egyptian Book of the Dead, lapis lazuli, in the shape of an eye set in gold, was considered an amulet of great power. On the last day of the month, an offering was made before this symbolic eye, for it was believed that, on that day, the supreme being placed such an image on his head.

The ancient royal Sumerian tombs of Ur, located near the Euphrates River in lower Iraq, contained more than 6000 beautifully executed lapis lazuli statuettes of birds, deer, and rodents as well as dishes, beads, and cylinder seals. These carved artifacts undoubtedly came from material mined in Badakhshan in northern Afghanistan. Much Sumerian and Akkadian poetry makes reference to lapis lazuli as a gem befitting royal splendor.

In ancient times, lapis lazuli was known as sapphire,[6] which is the name that is used today for the blue corundum variety sapphire. It appears to have been the sapphire of ancient writers because Pliny refers to sapphirus as a stone sprinkled with specks of gold. A similar reference can be found in the Hebrew Bible in Job 28:6.

The Romans believed that lapis was a powerful aphrodisiac. In the Middle Ages, it was thought to keep the limbs healthy, and free the soul from error, envy and fear.

It was once believed that lapis had medicinal properties. It was ground down, mixed with milk and applied as a dressing for boils and ulcers.

Many of the blues in painting from medieval Illuminated manuscripts to Renaissance panels were derived from lapis lazuli. Ground to a powder and processed to remove impurities and isolate the component lazurite, it forms the pigment ultramarine. This clear, bright blue, which was one of the few available to painters before the 19th century, cost a princely sum. As tempera painting was superseded by the advent of oil paint in the Renaissance, painters found that the brilliance of ultramarine was greatly diminished when it was ground in oil and this, along with its cost, led to a steady decline in usage. Since the synthetic version of ultramarine was discovered in the 19th century (along with other 19th century blues, such as cobalt blue), production and use of the natural variety has almost ceased, though several pigment companies still produce it and some painters are still attracted to its brilliance and its romantic history.

Poetry/literature

Lapis Lazuli is a poem written by William Butler Yeats. Text available at Readprint.com It is also mentioned in Yeats' poem Oil and Blood.

As noted above, lapis lazuli is also repeatedly mentioned in the Sumerian and Akkadian Epic of Gilgamesh. For instance, the Bull of Heaven's horns are composed of Lapis lazuli.

Lapis Lazuli is also mentioned in Robert Browning's 'The Bishop Orders His Tomb at Saint Praxed's Church'.

Lapis lazuli also makes an appearance in Marianne Moore's poem, "A Talisman" - which is quoted by T. S. Eliot in his "Introduction to Selected Poems [of Marianne Moore]." The stanza of Moore's poem reads: "Of lapis-lazuli,/A scarab of the sea,/With wings spread-". Eliot, in the next paragraph, raises the question: "I cannot see what a bird carved of lapis-lazuli should be doing with coral feet; but even here the cadence, the use of rhyme, and a certain authoritativeness of manner distinguish the poem."

In Lorna Crozier's poem "The Memorial Wall", "a young man who'd come from Montana to find his brother's name paints the side door lapis lazuli".

In D.H. Lawrence's novel, Women in Love, a female character attempts to kill her lover after a quarrel by smashing his head with a lapis lazuli paperweight.

In Robert A. Heinlein's novel, Time Enough for Love, the centuries old main character, Lazarus Long, names one of his two twin cloned daughters Lapis Lazuli.

David Foster Wallace's essay "A Supposedly Fun Thing I'll Never Do Again" makes repeated reference to what author Frank Conroy, in a brochure for Caribbean Cruise Lines, dubbed "the lapis lazuli dome of the sky." The more Wallace considers the phrase, the more disingenuous, inexpressive and manufactured it seems to him.

In Katherine Roberts' novel The Babylon Game (the second novel in the series The Seven Fabulous Wonders), the royal seal found by Tiamat in the Princess' Garden is made out of lapis lazuli - the material used for all royal seals.

In Emily Rodda's children's series Deltora Quest, the lapis lazuli, or "Heavenly Stone," is one of the seven lost gems of Deltora.

A lapis lazuli inlaid spitton forms the central theme of a part of Salman Rushdie's Midnight's Children.

Notes

  1. ^ a b c Bowersox & Chamberlin 1995
  2. ^ Mindat.org
  3. ^ Mindat - Lazurite
  4. ^ Senning, Alexander (2007). Elsevier's Dictionary of Chemoetymology: The Whies and Whences of Chemical Nomenclature and Terminology. Amsterdam: Elsevier, p. 224. 0444522395. “lapis lazuli (lazurite) Na3Ca(Si3Al3)O12S, derived from lapis (Latin: stone) and, ultimately, Lajward, a place in Turkestan” 

    Weekley, Ernest (1967). An Etymological Dictionary of Modern English. New York: Dover, p. 97. “azure. Orig. the precious stone lapis lazuli, later, blue in heraldry. F. azur (Chanson de Roland); cf. It. azzurro, Sp. azul (OSp. azur), from Arab. lazward, Pers. lajward, a place in Turkestan whence the stone was procured.” 

    The etymology of lapis lazuli directs us also to Persia. The word occurs first in the fourteenth century as a compound of Latin lapis 'stone' and Mediaeval Latin lazulum from Arabic lāzaward from Persian lāzhuward 'lapis lazuli'.

    mlat. lazurium; < arab. lāzaward/lāzuward < perz. lāžward.
    De steen is genoemd naar de mijnen in Lāžward (Turkestan).
  5. ^ Oldershaw 2003
  6. ^ Schumann, Walter [2002] (2006). "Sapphire", Gemstones of the World, Trans. Annette Englander & Daniel Shea, Newly Revised & Expanded 3rd, New York: Sterling, p. 102. “In antiquity and as late as the Middle Ages, the name sapphire was understood to mean what is today described as lapis lazuli.” 

References

  • Bowersox, Gary W. & Chamberlin, Bonita E. (1995), , Tucson, AZ: Geoscience Press.
  • Oldershaw, Cally (2003), , , Toronto: Firefly Books.


 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Lapis_lazuli". A list of authors is available in Wikipedia.
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