( Fr- albâtre; Ger- Alabaster; Nor- alabast; Rus- )
A. Alabaster. 19th Century egg atop a leaf carving (greatest dimension - ca. 13 cm). R.S. Dietrich collection. (© photo by Dick Dietrich)
B. Alabaster piece, "Guardian Spirit" (width - ca. 26 cm), sculpted from Colorado alabaster by Dennis R. Christy, an Ojibwa. Saginaw-Chippewas' Soaring Eagle collection. (photo by D.R. Christy)
C. Alabaster owl, (height - ca. 50 cm), sculpted from Utah alabaster by Dennis R. Christy. Ron Koch collection. (photo by D.R. Christy)
DESCRIPTION: Alabaster is
massive variety of gypsum.
Colors - white, off-white, reddish, golden yellow, salmon-orange, yellowish brown and brown -- some of these colors are due to natural staining -- with some occurrences exhibiting color banding
Light transmission - subtransparent to subtranslucent
Luster - pearly to subvitreous
Miscellany - some masses are chatoyant.
OTHER NAMES: Geologists refer to this rock variously as rock gypsum, gypsum (unmodified), gypsite or gyprock. Some rock gypsum comprises mappable units that have been given formal stratigraphic unit designations (see Appendix B, Glossary) - e.g., the Castile Gypsum of west Texas and the Kingfisher Creek Gypsum Bed in west-central Oklahoma.
USES: Fine, granular masses of gyprock have been fashioned into such things as vases, urns, figurines, sculptures and diversely shaped -- e.g., bowl-shaped -- devices utilized as fixtures for indirect lighting, some that date back to at least the 5th century B.C. (Bass, 2002). The utilization of translucent color-layered alabaster as "chimneys" for candle-holding hurricane lamps is a present-day extension of this last listed use. In addition, some especially fine examples of the use of alabaster for sculpting statues, statuettes, and steles in the early Sumerian commerce centers, ancient Yemen and Ur, are illustrated in articles by Covington (1998 and 2003). Also, as Pough (1996) has noted, "Stony bands of massive Italian gypsum, known as alabaster, are carved and dyed in Florence and fibrous warm-hued chatoyant veins known as satin spar are Russian sculptors' grist."
OCCURRENCES: Rock gypsum suitable for use as a gemrock occurs in many sedimentary sequences; the gypsum is typically interbedded with limestone and/or marl, red shales, claystone and/or rock salt. It also has been found in saline lake deposits and in the gypsum-rich caprock of salt domes.
NOTEWORTHY LOCALITIES: Castellina in the Volterra district, Tuscany, Italy and near Chellaston, Derbyshire, England. And, the following statement of Stone et al. (1920, p.43) -- "Fine-grained semitranslucent rock gypsum or alabaster ... used by sculptors and artists for statuary and other forms of decoration ... is not quarried in this country [United States of America] for this purpose." -- should be disregarded as no longer true. See, for example, figures B and C; also, I recall that in the early 1930s I saw diverse articles marketed as carved from alabaster from the vicinity of Niagara Falls (New York and Ontario). And, more recently I have seen several pinkish alabaster articles noted as being fashioned from alabaster said to have been quarried near Fort Collins, Colorado.l
The designation alabaster is of ancient origin. According to OED
(1989 ed.) the Greek ᾀλάβαστρος -- is "said to be from name of a
town in Egypt." Mitchell (1979), however, notes that all that
apparently is known is that it is "from alabastrites, the stone out of
which a vase called an alabastron
was made." In addition, however, it is known that this name
was also applied in ancient times to "onyx marble" (see
TRAVERTINE entry), which had similar uses.
gypsum readily takes on stains of just about any color. Several
stained pieces are marketed as substitutes for other gemrocks including
jade (see THE JADES, Figure C). Dyed, and in some cases
also waxed, alabaster has been found in some antique jewelry -- e.g.,
as beads in multicolored (and commonly also multicomponent)
Poppy oil or some acrylic has been applied -- usually prior to final
polishing (with or without wax) -- to get the desired color. Another
recorded treatment involves placing alabaster in cold
water, slowly heating the water to the boiling point, and then slowly
cooling it to room temperature. -- Apparently this treatment hardens
it, or at least makes it appear harder.
As a youngster, I recall treasuring a small barrel-shaped trinket carved from gypsum that I was told came from beneath Niagara Falls. The material was marketed as Niagara spar or Falls spar. Later, while attending Colgate University, we students were repeatedly told the tale of the "Cardiff Giant": This large stone "man" was carved from gypsum; buried near Cardiff, Onondaga County, New York; subsequently "discovered" and advertised as a prehistoric giant man; exhibited for several years for viewing "at a price" by its owners; and later pronounced a fraud by Harold O. Whitnall, one of my erstwhile geology professors.
Some eggs carved from gypsum have been used -- especially in Russia -- as Easter gifts. Some similar alabaster eggs, dyed in brilliant colors with a marbleized pattern and reportedly from Tuscany, Italy, have been marketed during the last few years for use as decorative Easter eggs.
Alabastra or Egyptian alabaster - Most of the so-designated material used in ancient Egypt for making many kinds of vessels, was calcite (now widely referred to as travertine and some of its synonyms -- see TRAVERTINE entry) rather than gypsum. Unfortunately, this incorrect use of terms has persisted in many quarters: This is so because Egyptologists traditionally refer to the banded onyx marble of bowls as alabaster. - [greater hardness (H. 3) and effervesces with dilute HCl].
***Cast alabaster - Some items, especially figurines, that have the appearance of carvings are said to be cast alabaster. This, of course, indicates that they consist of either masses of gypsum deposited from man-made solutions or particles of gypsum bonded by, for example, a resin that gained their shapes as the result of being cast in molds. - [Fortunately, these are usually marketed as cast alabaster.].
***Plaster of Paris - when dyed or oiled, this man-made concoction closely resembles alabaster - [Non-macroscopic procedures may be required.].
REFERENCES: Jones, 1986; Smith et al.,1973; Stone et al.,1920; Withington, 1962; Withington and Jaster, 1960.; General, historical and mineralogical information, some of which is less than well-founded and/or not widely applicable and/or accepted, along with citations to a few more recent publications, are given on the following web site: http://en.wikipedia.org/wiki/Alabaster <accessed 18 January 2014>
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R. V. Dietrich
Last update: 18 January 2014
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