Alabaster is a mineral and 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, [1] and (ii) the fine-grained, banded type of calcite. [2]
Chemically, gypsum is a hydrous sulfate of calcium, whereas calcite is a carbonate of calcium. [2] [3] As types of alabaster, gypsum and calcite have similar properties, such as light color, translucence, and soft stones that can be carved and sculpted; thus the historical use and application of alabaster for the production of carved, decorative artefacts and objets d’art . [3] Calcite alabaster also is known as onyx-marble, Egyptian alabaster, and Oriental alabaster, which terms usually describe either a compact, banded travertine stone [2] or a stalagmitic limestone colored with swirling bands of cream and brown. [3]
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, effervesces when treated with hydrochloric acid while gypsum alabaster remains almost unaffected. [4]
The English word "alabaster" was borrowed from Old French alabastre, in turn derived from Latin alabaster, and that from Greek ἀλάβαστρος (alábastros) or ἀλάβαστος (alábastos). The Greek words denoted a vase of alabaster. [5]
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. [6] [7] 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. [8] [9]
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". [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 with dishwashing 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 an ornamental stone, especially for ecclesiastical 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 a lathe for round shapes, carved into three-dimensional sculptures, chiselled to produce low relief figures or decoration; and then given an elaborate finish that reveals its transparency, colour, and texture. [13]
In order to diminish the translucency 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 di Castellina". [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 of coral that is called "alabaster coral" is produced.
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. [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 in medieval ones, especially in Italy. [16] Large sheets of Aragonese gypsum alabaster are used extensively in the Cathedral of Our Lady of the Angels, [17] dedicated in 2002 by the Los 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 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 stalagmitic deposit from the floor and walls of limestone caverns, 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. [4]
Egyptian alabaster has been worked extensively near Suez [ citation needed ] and Assiut. [8]
This stone variety is the "alabaster" of the ancient Egyptians and Bible and is often termed Oriental alabaster, since the early examples came from the Far East. The Greek 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;[ 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 called alabastra; the vessel name has been suggested as a possible source of the mineral name. In Egypt, craftsmen used alabaster for canopic jars 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. [4]
Algerian onyx-marble has been quarried largely in the province of Oran.[ citation needed ]
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. [20]
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. [4]
Gypsum alabaster is softer than calcite alabaster. It was used primarily in medieval Europe, and is also used in modern times.
"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 7 feet (2.1 m) 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. [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 deity Abu dating to the first half of the 3rd millennium BC, which is kept in New York. [22]
This section relies largely or entirely on a single source .(May 2021) |
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. [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 in Tertiary basins. [17] The most important site is the Fuentes-Azaila area, in the Tertiary Ebro Basin. [17] The other is the Calatayud-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 in Zaragoza 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 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. [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]
In modern Europe, the centre of the alabaster trade is Florence, Italy. Tuscan alabaster occurs in nodular masses embedded in limestone, interstratified with marls 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. [4]
In the 3rd century BC the Etruscans used the alabaster of Tuscany from the area of modern-day Volterra to produce funeral urns, possibly taught by Greek artists. [23] During the Middle 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 sculptor Albino Funaioli. [24] After a short slump, the industry was revived again by the sale of mass-produced mannerist Expressionist sculptures. It was further enhanced in the 1920s by a new branch that created ceiling and wall lamps in the Art Deco style, culminating in participation at the 1925 International Exposition of Modern Industrial and Decorative Arts in Paris. [24] Important names in the evolution of alabaster use after World War II are Volterran Umberto Borgna, the "first alabaster designer", and later on the architect and industrial designer Angelo Mangiarotti. [25]
Gypsum alabaster is a common mineral, which occurs in England in the Keuper marls of the 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. [4]
In the 14th and 15th centuries the carving into small statues and sets of relief panels for altarpieces 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 tomb 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 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. [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 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.
Chronological list of examples:
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk chalk. Gypsum also crystallizes as translucent crystals of selenite. It forms as an evaporite mineral and as a hydration product of anhydrite. The Mohs scale of mineral hardness defines gypsum as hardness value 2 based on scratch hardness comparison.
Marble is a metamorphic rock consisting of carbonate minerals (most commonly calcite (CaCO3) or dolomite (CaMg(CO3)2) that have recrystallized under the influence of heat and pressure. It has a crystalline texture, and is typically not foliated (layered), although there are exceptions.
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses.
Celestine (the IMA-accepted name) or celestite is a mineral consisting of strontium sulfate (SrSO4). The mineral is named for its occasional delicate blue color. Celestine and the carbonate mineral strontianite are the principal sources of the element strontium, commonly used in fireworks and in various metal alloys.
Travertine is a form of terrestrial limestone deposited around mineral springs, especially hot springs. It often has a fibrous or concentric appearance and exists in white, tan, cream-colored, and rusty varieties. It is formed by a process of rapid precipitation of calcium carbonate, often at the mouth of a hot spring or in a limestone cave. In the latter, it can form stalactites, stalagmites, and other speleothems. It is frequently used in Italy and elsewhere as a building material. Similar deposits formed from ambient-temperature water are known as tufa.
Onyx is the parallel-banded variety of chalcedony, a silicate mineral. Agate and onyx are both varieties of layered chalcedony that differ only in the form of the bands. Onyx has parallel bands, while agate has curved bands. The colors of its bands range from black to almost every color. Specimens of onyx commonly contain bands of black or white or both. Onyx, as a descriptive term, has also been applied to parallel-banded varieties of alabaster, marble, calcite, obsidian, and opal, and misleadingly to materials with contorted banding, such as "cave onyx" and "Mexican onyx".
A speleothem is a geological formation made by mineral deposits that accumulate over time in natural caves. Speleothems most commonly form in calcareous caves due to carbonate dissolution reactions. They can take a variety of forms, depending on their depositional history and environment. Their chemical composition, gradual growth, and preservation in caves make them useful paleoclimatic proxies.
Selenite, satin spar, desert rose, and gypsum flower are crystal habit varieties of the mineral gypsum.
Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the orthorhombic barium (baryte) and strontium (celestine) sulfates, as might be expected from the chemical formulas. Distinctly developed crystals are somewhat rare, the mineral usually presenting the form of cleavage masses. The Mohs hardness is 3.5, and the specific gravity is 2.9. The color is white, sometimes greyish, bluish, or purple. On the best developed of the three cleavages, the lustre is pearly; on other surfaces it is glassy. When exposed to water, anhydrite readily transforms to the more commonly occurring gypsum, (CaSO4·2H2O) by the absorption of water. This transformation is reversible, with gypsum or calcium sulfate hemihydrate forming anhydrite by heating to around 200 °C (400 °F) under normal atmospheric conditions. Anhydrite is commonly associated with calcite, halite, and sulfides such as galena, chalcopyrite, molybdenite, and pyrite in vein deposits.
Pamukkale, meaning "cotton castle" in Turkish, is a natural site in Denizli Province in southwestern Turkey. The area is famous for a carbonate mineral left by the flowing of thermal spring water. It is located in Turkey's Inner Aegean region, in the River Menderes valley, which has a temperate climate for most of the year.
Polychrome is the "practice of decorating architectural elements, sculpture, etc., in a variety of colors." The term is used to refer to certain styles of architecture, pottery, or sculpture in multiple colors.
Flowstones are sheetlike deposits of calcite or other carbonate minerals, formed where water flows down the walls or along the floors of a cave. They are typically found in "solution caves", in limestone, where they are the most common speleothem. However, they may form in any type of cave where water enters that has picked up dissolved minerals. Flowstones are formed via the degassing of vadose percolation waters.
Limescale is a hard, chalky deposit, consisting mainly of calcium carbonate (CaCO3). It often builds up inside kettles, boilers, and pipework, especially that for hot water. It is also often found as a similar deposit on the inner surfaces of old pipes and other surfaces where hard water has flowed. Limescale also forms as travertine or tufa in hard water springs.
Żebbuġ is a village and an administrative unit of Malta, in the northwest coast of the island of Gozo. It is located close to Għarb and Għasri and is built on two hilltop plateaus, Ta' Abram and Ix-Xagħra taż-Żebbuġ. The fishing port and tourist resort of Marsalforn lies within the Żebbuġ Council. The village has a population of 2,956, which makes it the fifth largest in Gozo, after Xewkija.
A stone sculpture is an object made of stone which has been shaped, usually by carving, or assembled to form a visually interesting three-dimensional shape. Stone is more durable than most alternative materials, making it especially important in architectural sculpture on the outside of buildings.
Etruscan art was produced by the Etruscan civilization in central Italy between the 10th and 1st centuries BC. From around 750 BC it was heavily influenced by Greek art, which was imported by the Etruscans, but always retained distinct characteristics. Particularly strong in this tradition were figurative sculpture in terracotta, wall-painting and metalworking especially in bronze. Jewellery and engraved gems of high quality were produced.
Alabaster is a name applied to certain minerals, mainly gypsum and calcite. Alabaster may also refer to:
Hardstone carving, in art history and archaeology, is the artistic carving of semi-precious stones, such as jade, rock crystal, agate, onyx, jasper, serpentinite, or carnelian, and for objects made in this way. Normally the objects are small, and the category overlaps with both jewellery and sculpture. Hardstone carving is sometimes referred to by the Italian term pietre dure; however, pietra dura is the common term used for stone inlay work, which causes some confusion.
Calcareous sinter is a freshwater calcium carbonate deposit, also known as calc-sinter. Deposits are characterised by low porosity and well-developed lamination, often forming crusts or sedimentary rock layers. Calcareous sinter should not be confused with siliceous sinter, which the term sinter more frequently refers to. It has been suggested that the term "sinter" should be restricted to siliceous spring deposits and be dropped for calcareous deposits entirely.
The Jar of Xerxes I is a jar in calcite or alabaster, an alabastron, with the quadrilingual signature of Achaemenid ruler Xerxes I, which was discovered in the ruins of the Mausoleum at Halicarnassus, in Caria, modern Turkey, at the foot of the western staircase. It is now in the British Museum, though not currently on display.