Calcite alabaster: The tomb ofTutankhamun (d. 1323 BC) contained a practicalobjet d’art, a cosmetics jar made of Egyptian alabaster, which features a lid surmounted by a lioness (goddessBast).
Alabaster is amineral and a softrock used for carvings and as a source ofplaster powder. Archaeologists, geologists, and the stone industry have different definitions for the wordalabaster. In archaeology, the termalabaster includes objects and artefacts made from two different minerals: (i) the fine-grained, massive type ofgypsum,[1] and (ii) the fine-grained, banded type ofcalcite.[2]
Chemically, gypsum is ahydroussulfate ofcalcium, whereas calcite is acarbonate of calcium.[2][3] As types of alabaster, gypsum and calcite have similar properties, such as light color, translucence, and soft stones that can becarved and sculpted; thus the historical use and application of alabaster for the production of carved, decorative artefacts andobjets d’art.[3] Calcite alabaster also is known as onyx-marble, Egyptian alabaster, and Oriental alabaster, which terms usually describe either a compact, bandedtravertine stone[2] or astalagmiticlimestone colored with swirling bands of cream and brown.[3]
Alabaster artefact: A composite bust of the EmperorSeptimius Severus; the head is marble and the bust is alabaster.
In general, ancient alabaster is calcite in the widerMiddle East, includingEgypt andMesopotamia, while it is gypsum in medievalEurope. 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,effervesces when treated withhydrochloric acid while gypsum alabaster remains almost unaffected.[4]
Alabaster windows in the Church of Santa Maria la Mayor ofMorella, Spain (built 13th–16th centuries)
The English word "alabaster" was borrowed from Old Frenchalabastre, in turn derived fromLatinalabaster, and that fromGreekἀλάβαστρος (alábastros) orἀλάβαστος (alábastos). The Greek words denoted a vase of alabaster.[5]
The name may be derived further fromancient Egyptiana-labaste, which refers to vessels of the Egyptian goddessBast. She was represented as a lioness and frequently depicted as such in figures placed atop these alabaster vessels.[6][7] Ancient Roman authorsPliny the Elder andPtolemy wrote that the stone used for ointment jars calledalabastra came from a region of Egypt known as Alabastron or Alabastrites.[8][9]
The purest alabaster is a snow-white material of fine uniform grain, but it often is associated with an oxide ofiron, which produces brown clouding and veining in the stone. The coarser varieties of gypsum alabaster are converted by calcination intoplaster of Paris, and are sometimes known as "plaster stone".[4]
The softness of alabaster enables it to be carved readily into elaborate forms, but its solubility in water renders it unsuitable for outdoor work.[4] If alabaster with a smooth, polished surface is washed withdishwashing liquid, it will become rough, dull and whiter, losing most of its translucency and lustre.[10] The finer kinds of alabaster are employed largely as anornamental stone, especially forecclesiastical decoration and for the rails of staircases and halls.[4][11]
Alabaster is mined and then sold in blocks to alabaster workshops.[12] There they are cut to the needed size ("squaring"), and then are processed in different techniques:turned on alathe for round shapes,carved into three-dimensionalsculptures,chiselled to producelow relief figures or decoration; and then given an elaborate finish that reveals its transparency, colour, and texture.[13]
In order to diminish thetranslucency 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 "marmo diCastellina".[4]
Alabaster is a porous stone and can be dyed into any colour or shade, a technique used for centuries.[13] For this the stone needs to be fully immersed in various pigment solutions and heated to a specific temperature.[13] The technique can be used to disguise alabaster. In this way an imitation ofcoral that is called "alabaster coral" is produced.
A calcite alabaster perfume jar from the tomb ofTutankhamun, d. 1323 BC
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 thealabastron type made inCyprus from theBronze Age into the Classical period.[14]
When cut into thin sheets, alabaster is translucent enough to be used for small windows.[15] It was used for this purpose in Byzantine churches and later inmedieval ones, especially inItaly.[16] Large sheets of Aragonese gypsum alabaster are used extensively in theCathedral of Our Lady of the Angels,[17] dedicated in 2002 by theLos Angeles, California, Archdiocese.[18] The cathedral incorporates special cooling to prevent the panes from overheating and turning opaque.[18] The ancients used the calcite type,[19] 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 dish from the Ancient Egyptian tomb of "U",Semerkhet
Calcite alabaster, harder than the gypsum variety, was used in ancient Egypt and the wider Middle East (exceptAssyrian palace reliefs), and also in modern times. It is found as either astalagmitic deposit from the floor and walls oflimestonecaverns, or as a kind oftravertine, 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) asonyx.[4]
Egyptian alabaster has been worked extensively nearSuez[8] andAssiut.[8]
This stone variety is the "alabaster" of theancient Egyptians andBible and is often termedOriental alabaster, since the early examples came from theFar East. TheGreek namealabastrites is said to be derived from the town of Alabastron inEgypt, where the stone was quarried. The locality may owe its name to the mineral;[dubious –discuss] though the origin of the mineral name is obscure[4]
The "Oriental" alabaster was highly esteemed for making small perfume bottles or ointment vases calledalabastra; the vessel name has been suggested as a possible source of the mineral name. In Egypt, craftsmen used alabaster forcanopic jars and various other sacred and sepulchral objects. Thesarcophagus of Seti I, found inhis tomb nearThebes, is on display inSir John Soane's Museum,London; it is carved in a single block of translucent calcite alabaster from Alabastron.[4]
Calcite alabaster was quarried in ancientIsrael in the cave known as the Twins Cave nearBeit Shemesh.Herod used this alabaster for baths in his palaces.[20]
"Mosul marble" is a kind of gypsum alabaster found in the north of modernIraq, which was used for theAssyrian 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 7 feet (2.1 m) high. TheLion Hunt of Ashurbanipal and militaryLachish reliefs, both 7th century BC and in theBritish Museum, are some of the best known.
Gypsum alabaster was widely used for smallsculpture for indoor use in the ancient world, especially in ancient Egypt andMesopotamia. 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 alabasterartifacts dating to the late4th millennium BC also have been found inTell Brak (modernNagar), inSyria.[21]
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 deityAbu dating to the first half of the 3rd millennium BC, which is kept in New York.[22]
Much of the world's alabaster is extracted from the centre of theEbro Valley inAragon,Spain, which has the world's largest known exploitable deposits.[17] 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.[17][unreliable source] There are two separate sites in Aragon, both are located inTertiary basins.[17] The most important site is the Fuentes-Azaila area, in the TertiaryEbro Basin.[17] The other is theCalatayud-Teruel Basin, which divides the Iberian Range in two main sectors (NW and SE).[17]
The abundance of Aragonese alabaster was crucial for its use in architecture, sculpture and decoration.[17] There is no record of use by pre-Roman cultures, so the first ones to use alabaster from Aragon may have been the Romans, who produced vessels from alabaster following the Greek and Egyptian models.[17] It seems that since the reconstruction of the Roman Wall inZaragoza in the 3rd century AD with alabaster, the use of this material became common in building for centuries.[17] Muslim Saraqusta (Zaragoza) was also called "Medina Albaida", the White City, due to the appearance of its alabaster walls and palaces, which stood out among gardens, groves and orchards by the Ebro and Huerva Rivers.[17]
The oldest remains in theAljafería 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.[17] In the 16th century sculptors in Aragon chose alabaster for their best works. They were adept at exploiting its lighting qualities and generally speaking the finished art pieces retained their natural color.[17]
Uplighter lamp, white and brown Italian alabaster, base diameter 13 cm (20th century)
In modernEurope, the centre of the alabaster trade isFlorence, Italy.Tuscan alabaster occurs in nodular masses embedded in limestone, interstratified withmarls ofMiocene andPliocene age. The mineral is worked largely by means of underground galleries, in the district ofVolterra. Several varieties are recognized—veined, spotted, clouded, agatiform, and others. The finest kind, obtained principally fromCastellina, 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, andLivorno.[4]
In the 3rd century BC theEtruscans used the alabaster of Tuscany from the area of modern-day Volterra to producefuneral urns, possibly taught by Greek artists.[23] During theMiddle Ages the craft of alabaster was almost completely forgotten.[23] A revival started in the mid-16th century, and until the beginning of the 17th century alabaster work was strictly artistic and did not expand to form a large industry.[24]
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.[24]
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.[24] Apart from the newly developed craft, artistic work became again possible, chiefly by Volterran sculptorAlbino Funaioli.[24] After a short slump, the industry was revived again by the sale of mass-produced manneristExpressionist sculptures. It was further enhanced in the 1920s by a new branch that created ceiling and wall lamps in theArt Deco style, culminating in participation at the 1925International Exposition of Modern Industrial and Decorative Arts in Paris.[24] Important names in the evolution of alabaster use afterWorld War II are VolterranUmberto Borgna, the "first alabaster designer", and later on the architect andindustrial designerAngelo Mangiarotti.[25]
In the 14th and 15th centuries the carving into small statues and sets ofrelief panels foraltarpieces was a valuablelocal 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, ontomb monuments, as the typical recumbent position suited the material's lack of strength, and it was cheaper and easier to work than good marble. After theEnglish Reformation the making of altarpiece sets was discontinued, but funerary monument work in reliefs and statues continued.
Alabaster is also found, in smaller quantity, atWatchet inSomerset, nearPenarth inGlamorganshire, and elsewhere. InCumbria 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 tofluorspar.[4]
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 inUnited States,Italy, andChina.
Alabaster Caverns State Park, nearFreedom, 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.
Calcite – Calcium carbonate mineral – mineral consisting of calcium carbonate (CaCO3); archaeologists and stone trade professionals, unlike mineralogists, call one variety of calcite "alabaster"
Gypsum – Soft calcium sulfate mineral – mineral composed of calcium sulfate dihydrate (CaSO4·2H2O); alabaster is one of its varieties
Anhydrite – Mineral, anhydrous calcium sulfate – a mineral closely related to gypsum
Calcium sulfate – Chemical derived from gypsum used in food and industry – the main inorganic compound (CaSO4) of gypsum
Fengite – translucent sheets of marble or alabaster used during the Early Middle Ages for windows instead of glass
Valencia Cathedral – Cathedral in Valencia, Spain – mainly 13th–14th century, Valencia, Spain; thelantern of the octagonal crossing tower
Orvieto Cathedral – Cathedral church in Umbria, Italy – 14th-century, Orvieto, Umbria, central Italy
St. Peter's Basilica – Catholic basilica and landmark in Vatican City – 17th century, Rome; alabaster window byBernini (1598–1680) used to create a "spotlight"
Church of All Nations – Church constructed 1919–1924 in Jerusalem – 1924, Jerusalem, architect:Antonio Barluzzi. Windows fitted with dyed alabaster panels.
Church of the Transfiguration – Franciscan church on Mount Tabor in Israel – 1924, Mount Tabor, architect: Antonio Barluzzi. Alabaster roofing was attempted.
^"Gypsum".Britannica.Archived from the original on 8 January 2017. Retrieved8 January 2017.
^abcMore 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]
^abc"Grove": R. W. Sanderson and Francis Cheetham. "Alabaster",Grove Art Online, Oxford Art Online, Oxford University Press, accessed 13 March 2013,subscriber link.
^Griswold, John (September 2000)."Care of Alabaster"(PDF).Conserve O Gram.15: 4.Archived(PDF) from the original on 2022-10-09 – via National Park Service.
^Hermary, Antoine, Mertens, Joan R.,The Cesnola Collection of Cypriot Art: Stone Sculpture, 2014, The Metropolitan Museum of Art,ISBN1588395502, 9781588395504,pp. 384-398
.jpg)
