Alabaster is a soft rock used for carvings and as a source of plaster powder. Archaeologists, geologists, and the stone industry have different definitions for the word alabaster. In archaeology, the term alabaster includes objects and artefacts made from two different minerals: (i) the fine-grained, massive type of gypsum,[ More About Alabaster and Travertine: Brief Guide explains the different definitions used by geologists, archaeologists, and the stone trade. Oxford University Museum of Natural History, 2012, [1]]
Chemically, gypsum is a hydrous sulfate of calcium, whereas calcite is a carbonate of calcium.["Grove": R. W. Sanderson and Francis Cheetham. "Alabaster", Grove Art Online, Oxford Art Online, Oxford University Press, accessed 13 March 2013, subscriber link.] Calcite alabaster also is known as onyx-marble, Egyptian alabaster, and Oriental alabaster, which terms usually describe either a compact, banded travertine stone
In general, ancient alabaster is calcite in the wider Middle East, including Egypt and Mesopotamia, while it is gypsum in medieval Europe. Modern alabaster is most likely calcite but may be either. Both are easy to work and slightly soluble in water. They have been used for making a variety of indoor artwork and carving, as they will not survive long outdoors.
The two types are readily distinguished by their different hardness: gypsum alabaster (Mohs hardness 1.5 to 2) is so soft that a fingernail scratches it, while calcite (Mohs hardness 3) cannot be scratched in this way but yields to a knife. Moreover, calcite alabaster, being a carbonate, effervescence when treated with hydrochloric acid while gypsum alabaster remains almost unaffected.[ Endnotes:
]
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M. Carmichael, Report on the Volterra Alabaster Industry, Foreign Office, Miscellaneous Series, No. 352 (London, 1895)
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A. T. Metcalfe, "The Gypsum Deposits of Nottingham and Derbyshire," Transactions of the Federated Institution, vol. xii. (1896), p. 107
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J. G. Goodchild, "The Natural History of Gypsum," Proceedings of the Geologists' Association, vol. x. (1888), p. 425
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George P. Merrill, "The Onyx Marbles," Report of the U. S. National Museum for 1893, p. 539.
Etymology
The English word "alabaster" was borrowed from Old French
alabastre, in turn derived from
Latin alabaster, and that from
Greek language italic=no (
alábastros) or
italic=no (
alábastos). The Greek words denoted a vase of alabaster.
[ Alabastos, Henry George Liddell, Robert Scott, A Greek-English Lexicon, at Perseus]
The name may be derived further from ancient Egyptian a-labaste, which refers to vessels of the Egyptian goddess Bast. She was represented as a lioness and frequently depicted as such in figures placed atop these alabaster vessels.[ "alabaster", Merriam-Webster Online Dictionary] Ancient Roman authors Pliny the Elder and Ptolemy wrote that the stone used for ointment jars called alabastra came from a region of Egypt known as Alabastron or Alabastrites.
Properties and usability
The purest alabaster is a snow-white material of fine uniform grain, but it often is associated with an oxide of
iron, which produces brown clouding and veining in the stone. The coarser varieties of gypsum alabaster are converted by calcination into plaster of Paris, and are sometimes known as "plaster stone".
The softness of alabaster enables it to be carved readily into elaborate forms, but its solubility in water renders it unsuitable for outdoor work.
Modern processing
Working techniques
Alabaster is mined and then sold in blocks to alabaster workshops.
There they are cut to the needed size ("squaring"), and then are processed in different techniques:
Turning on a
lathe for round shapes,
Stone carving into three-dimensional
,
to produce low relief figures or decoration; and then given an elaborate finish that reveals its transparency, colour, and texture.
Marble imitation
In order to diminish the
Translucent of the alabaster and to produce an opacity suggestive of true marble, the statues are immersed in a bath of water and heated gradually—nearly to the boiling point—in an operation requiring great care, because if the temperature is not regulated carefully, the stone acquires a dead-white, chalky appearance. The effect of heating appears to be a partial dehydration of the gypsum. If properly treated, it closely resembles true marble and is known as "
Marble di Castellina".
Dyeing
Alabaster is a porous stone and can be dyed into any colour or shade, a technique used for centuries.
For this the stone needs to be fully immersed in various pigment solutions and heated to a specific temperature.
The technique can be used to disguise alabaster. In this way an imitation of coral that is called "alabaster coral" is produced.
Types, occurrence, history
Typically only one type is sculpted in any particular cultural environment, but sometimes both have been worked to make similar pieces in the same place and time. This was the case with small flasks of the
alabastron type made in
Cyprus from the
Bronze Age into the Classical period.
[Hermary, Antoine, Mertens, Joan R., The Cesnola Collection of Cypriot Art: Stone Sculpture, 2014, The Metropolitan Museum of Art, , 9781588395504, pp. 384-398]
Window panels
When cut into thin sheets, alabaster is translucent enough to be used for small windows.
It was used for this purpose in Byzantine churches and later in
medieval ones, especially in
Italy.
Large sheets of Aragonese gypsum alabaster are used extensively in the Cathedral of Our Lady of the Angels,
dedicated in 2002 by the Los Angeles, California, Archdiocese.
The cathedral incorporates special cooling to prevent the panes from overheating and turning opaque.
The ancients used the calcite type,
while the modern Los Angeles cathedral employs gypsum alabaster. There are also multiple examples of alabaster windows in ordinary village churches and monasteries in northern Spain.
Calcite alabaster
Calcite alabaster, harder than the gypsum variety, was used in ancient Egypt and the wider Middle East (except Assyrian palace reliefs), and also in modern times. It is found as either a
stalagmite deposit from the floor and walls of
limestone , or as a kind of
travertine, similarly deposited in springs of calcareous water. Its deposition in successive layers gives rise to the banded appearance that the marble often shows on cross-section, from which its name is derived: onyx-marble or alabaster-onyx, or sometimes simply (and wrongly) as
onyx.
Egypt and the Middle East
Egyptian alabaster has been worked extensively near
Suez and
Assiut.
This stone variety is the "alabaster" of the and Bible and is often termed Oriental alabaster, since the early examples came from the Far East. The Greek language name alabastrites is said to be derived from the town of Alabastron in Egypt, where the stone was quarried. The locality may owe its name to the mineral; though the origin of the mineral name is obscure
The "Oriental" alabaster was highly esteemed for making small perfume bottles or ointment vases called alabastron; the vessel name has been suggested as a possible source of the mineral name. In Egypt, craftsmen used alabaster for and various other sacred and sepulchral objects. The sarcophagus of Seti I, found in his tomb near Thebes, is on display in Sir John Soane's Museum, London; it is carved in a single block of translucent calcite alabaster from Alabastron.
onyx-marble has been quarried largely in the province of Oran.
Calcite alabaster was quarried in ancient Israel in the cave known as the Twins Cave near Beit Shemesh. Herod used this alabaster for baths in his palaces.
North America
In
Mexico, there are famous deposits of a delicate green variety at
La Pedrara, in the district of
Tecali, near Puebla. Onyx-marble occurs also in the district of Tehuacán and at several localities in the US including
California,
Arizona,
Utah,
Colorado and
Virginia.
Gypsum alabaster
Gypsum alabaster is softer than calcite alabaster. It was used primarily in medieval Europe, and is also used in modern times.
Ancient and Classical Near East
"Mosul marble" is a kind of gypsum alabaster found in the north of modern
Iraq, which was used for the Assyrian palace reliefs of the 9th to 7th centuries BC; these are the largest type of alabaster sculptures to have been regularly made. The relief is very low and the carving detailed, but large rooms were lined with continuous compositions on slabs around high. The
Lion Hunt of Ashurbanipal and military
Lachish reliefs, both 7th century BC and in the
British Museum, are some of the best known.
Gypsum alabaster was widely used for small sculpture for indoor use in the ancient world, especially in ancient Egypt and Mesopotamia. Fine detail could be obtained in a material with an attractive finish without iron or steel tools. Alabaster was used for vessels dedicated for use in the cult of the deity Bast in the culture of the ancient Egyptians, and thousands of gypsum alabaster artifacts dating to the late 4th millennium BC also have been found in Tell Brak (modern Nagar), in Syria.[[6] ]
In Mesopotamia, gypsum alabaster was the material of choice for figures of deities and devotees in temples, as in a figure believed to represent the deity Abu dating to the first half of the 3rd millennium BC, which is kept in New York.[[7] ]
Aragon, Spain
Much of the world's alabaster is extracted from the centre of the
Ebro Valley in
Aragon,
Spain, which has the world's largest known exploitable deposits.
According to a brochure published by the Aragon government, alabaster has elsewhere either been depleted, or its extraction is so difficult that it has almost been abandoned or is carried out at a very high cost.
There are two separate sites in Aragon, both are located in Tertiary basins.
The most important site is the Fuentes-
Azaila area, in the Tertiary
Ebro Basin.
The other is the
Calatayud-Teruel Basin, which divides the Iberian Range in two main sectors (NW and SE).
The abundance of Aragonese alabaster was crucial for its use in architecture, sculpture and decoration.
The oldest remains in the Aljafería Palace, together with other interesting elements like capitals, reliefs and inscriptions, were made using alabaster, but it was during the artistic and economic blossoming of the Renaissance that Aragonese alabaster reached its golden age.
Volterra (Tuscany)
In modern
Europe, the centre of the alabaster trade is Florence, Italy.
Tuscany alabaster occurs in nodular masses embedded in limestone, interstratified with
of
Miocene and
Pliocene age. The mineral is worked largely by means of underground galleries, in the district of
Volterra. Several varieties are recognized—veined, spotted, clouded, agatiform, and others. The finest kind, obtained principally from Castellina, is sent to Florence for figure-sculpture, while the common kinds are carved locally, into vases, lights, and various ornamental objects. These items are objects of extensive trade, especially in Florence,
Pisa, and
Livorno.
In the 3rd century BC the Etruscans used the alabaster of Tuscany from the area of modern-day Volterra to produce , possibly taught by Greek artists.
In the 17th and 18th centuries production of artistic, high-quality Renaissance-style artifacts stopped altogether, replaced by less sophisticated, cheaper items better suited for large-scale production and commerce. The new industry prospered, but the reduced need for skilled craftsmen left few of them still working. The 19th century brought a boom to the industry, largely due to the "traveling artisans" who offered their wares to the palaces of Europe, as well as to America and the East.
In the 19th century new processing technology was also introduced, allowing for the production of custom-made, unique pieces, as well as the combination of alabaster with other materials.[[8]Ecomuseo dell'alabastro, Volterra; official website]
England and Wales
Gypsum alabaster is a common mineral, which occurs in England in the
Keuper of the
English Midlands, especially at
Chellaston in
Derbyshire, at Fauld in
Staffordshire, and near Newark in
Nottinghamshire. Deposits at all of these localities have been worked extensively.
In the 14th and 15th centuries the carving into small statues and sets of relief panels for was a valuable local industry in Nottingham, as well as a major English export. These were usually painted, or partly painted. It was also used for the effigies, often life size, on , as the typical recumbent position suited the material's lack of strength, and it was cheaper and easier to work than good marble. After the English Reformation the making of altarpiece sets was discontinued, but funerary monument work in reliefs and statues continued.
In addition to the carvings still in Britain (particularly the Nottingham Castle Museum, British Museum, and Victoria and Albert Museum), trade in mineral alabaster (other than the antiques trade) is ongoing as far afield as the Musée de Cluny, Spain, and Scandinavia.
Alabaster is also found, in smaller quantity, at Watchet in Somerset, near Penarth in Glamorganshire, and elsewhere. In Cumbria it occurs largely in the New Red rocks, but at a lower geological horizon. The alabaster of Nottinghamshire and Derbyshire is found in thick nodular beds or "floors" in spheroidal masses known as "balls" or "bowls" and in smaller lenticular masses termed "cakes". At Chellaston, where the local alabaster is known as "Patrick", it has been worked into ornaments under the name of "Derbyshire spar"―a term more properly applied to fluorspar.
Black alabaster
Black alabaster is a rare anhydrite form of the gypsum-based mineral. The black form is found in only three veins in the world, one each in
United States,
Italy, and
China.
Alabaster Caverns State Park, near Freedom, Oklahoma, is home to a natural gypsum cave in which much of the gypsum is in the form of alabaster. There are several types of alabaster found at the site, including pink, white, and the rare black alabaster.
Gallery
Ancient and Classical Near East
Ebih-Il Louvre AO17551 n01.jpg| Statue of Ebih-Il, Mari on the Euphrates, made of gypsum alabaster (25th century BC)
File:Statuette_Goddess_Louvre_AO20127.jpg|Necropolis of Hillah, near Babylon. Alabaster, gold, terracotta and rubies. Musée du Louvre
Statue Ammaalay Louvre AO20282.jpg|Alabaster statue, Yemen (1st century BC)
File:Assyrian royal lion Hunt19.JPG|Assyrian relief; King Ashurbanipal spears a lion
European Middle Ages
Norbury, Derbyshire - Nicholas Fitzherbert.jpg|Alabaster sepulchral monument of Nicholas Fitzherbert, d. AD 1473, in St Mary and St Barlock's Church, Norbury, Derbyshire, England
File:Fossanova Abbey fc02.jpg|Alabaster windows in the choir of Fossanova Abbey church (12th century) in Latina, Italy
File:Casamari coro.jpg|Alabaster windows and rosette in the central apse of Casamari Abbey church (1203–1217) in Lazio, Italy
File:Orvieto083.jpg|Alabaster window in Orvieto Cathedral (14th century), Italy
Modern
Archaizing Relief of a Seated King and Attendants, late 19th century.jpg|Archaizing Relief of a Seated King and Attendants, Iran, Qajar art (late 19th century CE, in the style of 5th–4th century BC). Brooklyn Museum.
Alabasterlampe Umgang Oktogon erleuchtet.jpg|Alabaster lamp, Aachen Cathedral, Germany (early 20th century)
alabaster-satin spar.jpg|Objet d'art with gypsum alabaster base, showing typical mottling (modern)
See also
Mineralogy
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– mineral consisting of calcium carbonate (); archaeologists and stone trade professionals, unlike mineralogists, call one variety of calcite "alabaster"
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– mineral composed of calcium sulfate dihydrate (); alabaster is one of its varieties
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– a mineral closely related to gypsum
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– the main inorganic compound () of gypsum
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– translucent sheets of marble or alabaster used during the Early Middle Ages for windows instead of glass
Window and roof panels
Chronological list of examples:
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– 5th century, Ravenna
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– 6th century, Ravenna
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– mainly 13th–14th century, Valencia, Spain; the Roof lantern of the octagonal crossing tower
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– 14th-century, Orvieto, Umbria, central Italy
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– 17th century, Rome; alabaster window by Bernini (1598–1680) used to create a "spotlight"
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– 1924, Jerusalem, architect: Antonio Barluzzi. Windows fitted with dyed alabaster panels.
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– 1924, Mount Tabor, architect: Antonio Barluzzi. Alabaster roofing was attempted.
Further reading
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Harrell J.A. (1990), "Misuse of the term 'alabaster' in Egyptology", Göttinger Miszellen, 119, pp. 37–42.
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Mackintosh-Smith T. (1999), "Moonglow from Underground". Aramco World May–June 1999.[9]
External links
