{{otheruses}}

[[Image:alabaster.whole.600pix.jpg|thumb|200px|A modern uplighter lamp made from Italian alabaster (white and brown types). The base is 5 inches (13 cm) in diameter]]

[[Image:alabaster.base.600pix.jpg|thumb|200px|Detail of base of alabaster lamp]]

'''Alabaster''' (sometimes called '''satin spar''') is a name applied to varieties of two distinct [[mineral]]s: [[gypsum]] (a [[hydroxy|hydrous]] [[sulfur|sulfate]] of [[calcium]]) and [[calcite]] (a [[carbonate]] of calcium). The former is the alabaster of the present day; the latter is generally the alabaster of the ancients.

The two kinds are readily distinguished from each other by their relative '''hardnesses'''. The gypsum kind is so soft as to be readily scratched by a finger-nail ([[Mohs scale of mineral hardness|hardness]] 1.5 to 2), while the calcite kind is too hard to be scratched in this way ([[Mohs scale of mineral hardness|hardness]] 3), though it does yield readily to a knife. Moreover, the calcite alabaster, being a [[carbonate]], [[effervescence|effervesces]] on being touched with [[hydrochloric acid]], whereas the gypsum alabaster, when so treated, remains practically unaffected.

Due to the characteristic color of white alabaster, the term has entered the vernacular as a [[Metonymy|metonym]] for white things, particularly "alabaster skin".

==Etymology==
The origin of alabaster is in Middle English, through Old French ''alabastre'', in turn derived from Latin ''alabaster'' and Greek ''alabastros'' or ''alabastos'', the latter being the word for a vase made of alabaster. This may further derive from ancient Egyptian ''a-labaste'' (vessel of the goddess Bast).<ref>http://www.yourdictionary.com/alabaster</ref><ref>http://www.m-w.com/dictionary/alabaster</ref>

==Types==

=== Calcite alabaster ===
This substance, the "alabaster" of the [[Bible]], is often termed ''Oriental alabaster'', since the early examples came from the [[Far East]]. The [[Greek language|Greek]] name ''alabastrites'' is said to be derived from the town of Alabastron, in [[Egypt]], where the stone was quarried, but the locality probably owed its name to the mineral; the origin of the mineral-name is obscure, and it has been suggested that it may have had an [[Arabic language|Arabic]] origin. This "Oriental" alabaster was highly esteemed for making small perfume-bottles or ointment vases called alabastra, and this has been conjectured to be a possible source of the name. Alabaster was also employed in Egypt for [[canopic jar]]s and various other sacred and sepulchral objects. A splendid [[sarcophagus]], sculptured in a single block of translucent calcite alabaster from Alabastron, is in the [[Soane Museum]], [[London]]. This was discovered by [[Giovanni Belzoni]] in [[1817]] in the tomb of [[Seti I]] near [[Thebes, Egypt|Thebes]]. It was purchased by Sir [[John Soane]], having previously been offered to the [[British Museum]].

When cut in thin sheets, alabaster is translucent enough to be used for small windows, and has been used so in [[medieval]] churches, especially in [[Italy]]. Large alabaster sheets are used extensively in the [[Cathedral of Our Lady of the Angels]] (dedicated 2002) of the [[Roman Catholic Archbishop of Los Angeles|Los Angeles (California) Archdiocese]]. The cathedral incorporates special cooling to prevent the panes from overheating and turning opaque.

Calcite alabaster is either a [[stalagmite|stalagmitic]] deposit, from the floor and walls of [[limestone]] [[cavern]]s, or 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, whence it is known as onyx-marble or alabaster-onyx, or sometimes simply as [[onyx]] &mdash; a term which should, however, be restricted to siliceous minerals. Egyptian alabaster has been extensively worked near [[Suez]] and near [[Assiut]]; there are many ancient quarries in the hills overlooking the plain of [[Tell el Amarna]]. The
[[Algeria]]n onyx-marble has been largely quarried in the province of [[Oran]]. In [[Mexico]], there are famous deposits of a delicate green variety at [[La Pedrara]], in the district of [[Tecali]], near [[Puebla, Puebla|Puebla]]. Onyx-marble occurs also in the district of [[Tehuacán]] and at several localities in [[California]], [[Arizona]], [[Utah]], [[Colorado]] and [[Virginia]].

=== Gypsum alabaster ===<!-- This section is linked from [[Henry IV of England]] -->
[[Image:Statue Ammaalay Louvre AO20282.jpg|thumb|250PX|Statue made of Alabaster, south [[Arabia]], [[Yemen]]]]
In the present day, when the term "alabaster" is used without any qualification, it invariably means a [[Granularity|fine-grained]] variety of gypsum. This mineral, or alabaster proper, occurs in [[England]]. However, thousands of gypsum alabaster [[Artifact (archaeology)|artifacts]] dating to the late [[4th millennium BC]] have been found in [[Tell Brak]] (present day [[Nagar, Syria|Nagar]]), in [[Syria]] [http://www.metmuseum.org/Works_of_Art/viewOne.asp?dep=3&item=1988.323.8&viewmode=0&isHighlight=1]. And in [[Mesopotamia]], a gypsum alabaster [[sculpture]], believed to represent the god [[Abu]], dates to the first half of the [[3rd millennium BC]] [http://www.metmuseum.org/Works_of_Art/viewOne.asp?dep=3&viewmode=0&item=40%2E156].

Mineral alabaster occurs in [[England]] in the [[Keuper]] [[marl]]s of the [[Midlands]], especially at [[Chellaston]] in [[Derbyshire]], at [[Fauld]] in [[Staffordshire]] and near [[Newark, England|Newark]] in [[Nottinghamshire]]. All these localities have been extensively worked. Indeed, in the [[15th century]] its carving into [[icons]] and [[altarpiece]]s, was a valuable local industry in these areas, particularly [[Nottingham]], as well as a major English export. Besides examples of these still in Britain (especially at the [[Nottingham Castle Museum]], [[British Museum]] and [[Victoria and Albert Museum]]), that trade in itself (rather than just the antiques trade) has scattered examples as far afield as the [[Musée de Cluny]].

Alabaster is also found, though in subordinate 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 alabaster is known as "Patrick," it has been worked into ornaments under the name of "Derbyshire spar" &mdash; a term more properly applied to [[fluorspar]].

===Black alabaster===
''Black Alabaster'' is a rare form of the gypsum-based mineral found in only three veins in the world, one each in [[Oklahoma]] (USA), [[Italy]], and the [[People's Republic of 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.

==Uses==
[[Image:alabaster-satin spar.jpg|thumb|200px|left|Unlike the lamp, this fine alabaster sculpture is untreated: Its translucency and satiny lustre are preserved. Its base is of marble.]]

The finer kinds of alabaster are largely employed as an [[ornamental stone]], especially for [[ecclesiastical]] decoration and for the rails of staircases and halls. Its softness enables it to be readily carved into elaborate forms, but its solubility in water renders it inapplicable to outdoor work. The purest alabaster is a snow-white material of fine tiniforni grain, but it is often associated with an oxide of [[iron]], which produces brown clouding and veining in the stone. The coarser varieties of alabaster are converted by calcination into [[plaster of Paris]], whence they are sometimes known as "plaster stone."

On the continent of [[Europe]], the centre of the alabaster trade is [[Florence, Italy]]. [[Tuscany|Tuscan]] alabaster occurs in nodular masses embedded in limestone, interstratified with [[marl]]s of [[Miocene]] and [[Pliocene]] age. The mineral is largely worked by means of underground galleries, in the district of [[Volterra]]. Several varieties are recognized &mdash; veined, spotted, clouded, agatiform, and others. The finest kind, obtained principally from [[Castellina Marittima|Castellina]], is sent to Florence for figure-sculpture, while the common kinds are carved at a very cheap rate locally into vases, clock-cases and various ornamental objects, in which a large trade is carried on, especially in Florence, [[Pisa]] and [[Livorno]].

In order to diminish the [[Translucent|translucency]] of the alabaster and to produce an opacity suggestive of true marble, the statues are immersed in a bath of water and gradually heated nearly to the boiling-point &mdash; an operation requiring great care, for if the temperature is not carefully regulated, 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 very closely resembles true marble and is known as [[marmo di Castellina]]. Sulphate of lime (gypsum) was used also by the ancients, and was employed, for instance, in Assyrian sculpture, so that some of the ancient alabaster is identical with the modern stone.

Alabaster may be stained by digesting it, after being heated in various pigmentary solutions. In this way a good imitation of [[Coral (precious)|coral]] has been produced (alabaster coral).

== Further reading ==
J. A. Harrell, "Misuse of the term 'alabaster' in [[Egyptology]]," ''Göttinger Miszellen'', v. 119, [[1990]], pp. 37-42.

== See also ==
*{{Commons|Category:Alabaster|Alabaster}}
* [[List of minerals]]

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[[Category:Minerals]]
[[Category:Stone]]

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