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Ultramarine is a blue pigment, consisting essentially of a double silicate of aluminium and sodium with some sulfides or sulfates, and occurring in nature as a proximate component of lapis lazuli. Also known in the past as azzurrum ultramarine, azzurrum transmarinum, azzuro oltramarino, azur d'Acre, pierre d'azur, Lazurstein. Current terminology for ultramarine include natural ultramarine (English), outremer lapis (French), Ultramarin echt (German), oltremare genuino (Italian), and ultramar ino/ verdaero (Spanish). The pigment color code is P. Blue 29 77007. Ultramarine is the most complex of the mineral pigments, a complex sulfur-containing sodio- silicate (Na8-10Al6Si6O24S2-4), essentially a mineralized limestone containing a blue cubic mineral called lazurite. Some chloride is often present in the crystal lattice as well. The blue color of the pigment is due to the S3- radical anion, which contains an unpaired electronThe electron (also called negatron commonly represented as e&minus is a subatomic particle. In an atom the electrons surround the nucleus of protons and neutrons in an electron configuration. Electrons have the smallest electrical charge and when they mov.
The first noted use of lapis lazuli as a pigment can be seen in the 6th- and 7th-century AD cave paintings in AfghanistanAfghanistan ( Dari/ Pashtu: Afgnistn is a country in Central Asia. It is bordered by Iran in the west, Pakistan in the south and east, Turkmenistan, Uzbekistan and Tajikistan in the north, and China in the easternmost part of the country. It is among the temples, near the most famous source of the mineral. Lapis lazuli has also been identified in ChineseThis article is on the geographic and cultural entity. For other meanings, see China (disambiguation). China ( Traditional Chinese: , Simplified Chinese: , Hanyu Pinyin: Zhongguo, Wade-Giles: Chung-kuo) is a country in continental East Asia with some oute paintings from the 10th and 11th centuries and in IndiaThe Republic of India is a large multicultural country in South Asia, with a population of over one billion. The Indian economy is the fourth largest in the world, in terms of purchasing power parity, and is the world's second-fastest growing economy.n mural paintings from the 11th, 12th, and 17th centuries. Natural ultramarine is the most difficult pigment to grind by hand, and for all except the highest quality of mineral sheer grinding and washing produces only a pale grayish blue powder. At the beginning of the 13th century an improved method came into use, described by the 15th century artist Cennino Cennini . This process consisted of mixing the ground material with melted waxWax has traditionally referred to a substance that is secreted by bees ( beeswax) and used by them in constructing their honeycombs. In modern terms, wax is an imprecisely defined term generally understood to be a substance with properties similar to bees, resinResin is a hydrocarbon secretion formed in special resin canals of many plants, from many of which (for example, coniferous trees) it is exuded in soft drops from wounds, hardening into solid masses in the air. It may be obtained by making incisions in ths, and oilOil is a generic term for fluids that are not miscible with water. The name comes from Latin oleum for olive oil. Oil is frequently used to refer to petroleum an "oil shortage" generally means an inadequate supply of petroleum rather than cooking oil.s, wrapping the resulting mass in a cloth, and then kneading it in a dilute lye solution. The blue particles collect at the bottom of the pot, while the impurities and colorless crystals remain in the mass. This process was performed at least three times, with each successive extraction generating a lower quality material. The final extraction, consisting largely of colorless material as well as a few blue particles, brings forth ultramarine ash which is prized as a glaze for its pale blue transparency.
The pigment was most extensively used during the 14th through 15th centuries, as its brilliance complemented the vermilion and gold of illuminated manuscripts and Italian panel paintings. From the beginning of the 16th century this pigment began to be imported into Europe from "over the sea," as azurrum ultramarinum. As lapis lazuli only yields from 2 to 3% of the pigment, it is not surprising to learn that the pigment used to be weighed up with gold. It was valued chiefly on account of its brilliancy of tone and its inertness in opposition to sunlight, oil, and slaked lime. It is, however, extremely susceptible to even minute and dilute mineral acids and acid vapors. Dilute HCl, HNO3, and H2SO4 rapidly destroy the blue color, producing hydrogen sulfide (H2S) in the process. Acetic acid attacks the pigment at a much slower rate than mineral acids. Because of this susceptibility, ultramarine was only used for frescoes when it was applied "secco", in which the pigment was mixed with a binding medium and applied over dry plaster (such as Giotto di Bondone's frescos in the Cappella degli Scrovegni or Arena Chapel in Padua).
European artists used the pigment sparingly, reserving their highest quality blues for the robes of Mary and the Christ child. As a result of the high price, artists sometimes economized by using a cheaper blue, azurite, for under painting. Most likely imported to Europe through Venice, Italy, the pigment was seldom seen in German art or art from countries north of Italy. Due to a shortage of azurite in the late 16th and 17th century the demand for the already-expensive ultramarine increased dramatically. In 1814 Tassaert observed the spontaneous formation of a blue compound, very similar to ultramarine, if not identical with it, in a lime kiln at St. Gobain, which caused the Societé pour l'Encouragement d'Industrie to offer, in 1824, a prize for the artificial production of the precious colour. Processes were devised by Jean Baptiste Guimet ( 1826) and by Christian Gmelin ( 1828), then professor of chemistry in Tubingen; but while Guimet kept his process a secret Gmelin published his, and thus became the originator of the "artificial ultramarine" industry.
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