( Fr- jaïet, jais; Ger- Gagat/Pechkohle; Nor- gagat; Rus- )
JET, primarily Carbon. (See also COAL entry.)
A. Jet. Victorian Whitby Jet necklace: The Jet cross (height - ca. 4.0 cm), with carved circle motif, is suspended from oval links also carved from jet. (© photo by David Hartley, www.hhantiques.co.uk)
B. Jet. Art Nouveau necklace
the bottom, a stylized butterfly (width - ca. 4.5 cm), is shown; the
necklace is 36 cm long.
(© photo by Diana Breashears, www.trudystrunk.com) -- (The jet of this piece has been questioned as a glass simulant by viewers of this photograph; I have not had the opportunity to check the identity. )
C. Jet. Modern bracelet with
silver spacers (overall length - ca.
15 cm). (© courtesy
www.luckygemstones.com) -- (The jet of this
piece has been questioned as a glass simulant by viewers of this photograph; I
have not had the opportunity to check the identity. )
DESCRIPTION: Jet is a compact black
lignite (lignite is sometimes referred to as brown coal because it has
streak -- i.e.,
powdered lignite is brown). Although jet is usually characterized,
quite properly, as dense and homogeneous, much of it
exhibits a woody structure, which manifests its derivation from
Color - commonly characterized as jet-, pitch- or velvet black -- i.e., intense black
Light transmission - opaque
Luster - velvetlike; polished, brilliant
Breakage - conchoidal fracture
Miscellany - tends to feel warm; becomes electrically charged when rubbed with cloth and thus will pick up such things as small bits of paper; flammable, giving an odor like that of burning coal.
USES: For the most part in mourning jewelry -- e.g., brooches, pendants and beads, commonly faceted; for statuettes, carvings and souvenirs; as the base material for pietra dura; and rarely for such things as carved plaques and rather small vessels of several genre. An eight-foot long necklace ("rope") of polished jet is recorded by Crowningshield (1963).
OCCURRENCES: Within carbon-rich beds in predominantly shale strata. So far as the origin, Stutzer (1940, p.270) notes that "during the process of coal formation, wood fragments frequently become impregnated with dissolved products of decomposition ... [and a material is formed that is] dense and pitchlike. This process has sometimes but not very correctly been called 'gagatization,' because gagate, or jet, originates in a similar way by saturation of wood with organic substances, primarily hydrocarbons."
NOTEWORTHY LOCALITIES: Near the coast in the vicinity of Whitby, Yorkshire, England; Languedoc, France; Oviedo (formerly Asturias), Oviedo Province, Spain; El Paso County, Colorado.
term jet is usually indicated to be from Middle English after
Anglo-Norman geet, from the Latin gagates, from Greek gagates,
for Gagas, a town of Lycia (an ancient
region/Roman province on the Aegean Sea, southwest of Asia Minor). This
is particularly interesting (confusing?) when one considers the
currently prevalent status accorded gagate -- see under SIMULANTS
Jet is flamable, so one should avoid heating it. Also, anything made from jet should not be put in contact with acids because such contact tends to cause its surfaces to lose their luster.
Jet pieces apparently shaped by flint tools have been found with other paleolithic materials within caves in Canton Schaffhausen, Switzerland and in Belgium. A photograph of a necklace with carved jet beads – “made by Magdalenian craftsmen, ... [ca.]13,000 B.C.” – found near Petersfels, which is northeast of the Bodensee in southwestern Germany, is shown in Dubin (1987). Artifacts made from Whitby jet have been recorded as dating to at least the 2nd Century B.C -- the existence of this material, however, is doubted by some professional archaeologists. During the 1500s, many Rosary beads were made from jet, which was frequently dubbed "black Amber." Also, jet beads were among the artifacts found at the site of Raleigh Gilbert's house at Fort St. George, which was the 1607-08 English Popham Colony at the tip of Sabino Head, near the mouth of the Kennebec River, Maine (www.pophamcolony.org). It was not, however, until Queen Victoria mourned Albert and wore jet jewelry with her black attire, that jet gained real popularity; thereafter, it was considered widely -- especially in Great Britain -- to be the appropriate jewelry to wear at funerals. Along this line, at least in my mind, a remarkable (sub)parallel use is recorded on the following web site: www.luckygemstones.com/jet-jewelry-black mourning-gem.htm:. "The Pueblo Indians were known for burying Jet with their dead. A famous, exceptionally beautiful and well-made frog carved from Jet and inlaid with Turquoise eyes, was discovered in the Pueblo Bonito in 1896 by Mr. Pepper. It is believed these Indians thought Jet would protect them in the after-life."
Also noteworthy, I think, are the following selected descriptive lines in the English translation (King, 1865, p.388), of a poem said to have been written in the 4th Century A.D. and attributed to Orpheus:
" ... when Jet in rising clouds consumes,
The nose provoking with its pungent fumes.
Black as a coal, but yet of lustrous shine,
It blases up like torch of driest pine;..."
The fact that the chain links, as well as the
pendant, of the necklace shown as Figure A are jet was of special
interest to me, whose experience in small scale carving has been
limited to fashioning diverse things from peach pits. In answer
to my queries, David Hartley (personal communication, 2003) notes "To
learn to carve jet involved a 5/7 year apprenticeship to a master
carver. [and] links like
these were usually carved in two halves and joined by very fine
glue." In addition, he added "the only Jet that could be
carved and polished to this degree was from Whitby and is instantly
as such by an experienced dealer....[-- e.g.,] jet from Spain often
and with time fractured further [whereas] Whitby Jet never fractures in
this way, and is of a uniform color, without brown marks or
SIMULANTS: The designation jet is usually indicated to be from Middle English after Anglo-Norman geet, from the Latin gagates, from Greek gagates, after Gagas, a town of Lycia, which is (an ancient region/Roman province on the Aegean Sea, southwest of Asia Minor). - [see OCCURRENCES.].
Anthracite - a possible but, so far as I have been able to determine, never used substitute for jet; it does, however, have gemrock uses similar to those of jet - [See COAL entry.].
Asphaltic pyrobitumens - To date, I have not seen asphaltic pyrobitumens and related materials recorded as having been used as a jet substitute or even being used in jewelry or fashioned pieces. This indicated neglect seems odd because some of these substances have characteristics that would appear to make them quite suitable for such use. Examples of these substances, listed alphabetically, are albertite, anthraxolite, asphaltite, gilsonite, glance pitch, grahamite, impsonite, libolite, stellarite, unitaite (=unitahite), and wurtzilite. I have seen some of these materials labeled as coming from localities in the Uinta Basin, Utah and Montgomery County, Virginia; Alberta and Nova Scotia, Canada; and Angola. Each is considered as possibly derived by so-to-speak metamorphism of petroleum.
Augite - see Black minerals.
***Bakelite - a trademark name given to a number of synthetic resins and plastics, some black ones of which have been used as substitutes for jet - [Appearance usually suffices in that most, if not all, so-constituted items are molded rather than carved; also, these items commonly bear a trademark or patent notice.].
Black amber - see under OTHER NAMES subheading.
Black "coral" - marketplace name given a bryozoan from Hawaii. - [effervesces in dilute HCl].
Black minerals - e.g., black augite, garnet (melanite), sphalerite, spinel (hercynite), and tourmaline (schorl). - [Each is markedly harder than jet and feels cold as compared to jet (see Johnson, McClure & DeGhion, 1996).].
Cannel coal (candle coal in some records) - homogenous, dull, compact coal of bituminous grade. - [Has black streak; does not take a good polish, tends to be more brittle; can be seen under a simple microscope to consist largely of spores - see COAL entry.]
Chalcedony dyed black. - [superior hardness (H. ~7)].
***Crepe stone - black glass with a dull crepelike appearance, used especially in mourning jewelry. - [See Glass.].
Dolostone - A "quartzite and dolomite" rock, which on the basis of the description given seems likely to be a quartz-bearing dolostone, has been recorded as having been fashioned into a gemstone (Hargett, 1991). As illustrated, it is black and would apparently be a good substitute for such gemrocks as onyx or jet. -- Although Hargett does not indicate that the rock was dyed, it would seem very likely it was because black dolostones are rare, if indeed they exist. - [effervesces, albeit with a slow simmering, when attacked with dilute HCl].
***Ebonite (also called vulcanite) - black vulcanized – i.e., hardened – rubber, used in some mourning jewelry. - [Facets on ebonite used for beads (etc.) are formed by molding of the precursor fluid so the sharp edges characteristic of those generally produced by cutting and polishing jet are lacking; also, when touched with a hot needle, ebonite will emit the odor of burning rubber; and, some vulcanite tends to fade to a tan or olive-brown color when left in the sun for relatively long periods of time.].***French jet (a glass). - according to David Hartley (personal communication, 2003) "The most successful imitation [of Whitby Jet] was known as 'French Jet' and while it was able to imitate the lustre of polished Whitby Jet, it was cold and heavy in comparison to the real thing." - [The facets on this glass used for beads (etc.) are formed by molding of the precursor fluid and consequently lack the sharp edges common to those made by cutting and polishing jet; also, glass is not affected by a hot needle and is heavier than jet.].
Gagate (gagatite) - a coal-like rock that
resembles jet. Unfortunately, the literature about jet and
gagate is replete with ambiguities: Some writers have
used the terms interchangeably. And, to add to the
confusion -- especially for those of us who are interested in the
etymology of words -- see first sentence under the REMARKS
subheading and also the statement under OCCURRENCES.
***Gutta-percha - some of the mourning pieces of Victorian England were fashioned from this material, which may be described as a rubberlike substance that is derived from the latex of any of several tropical trees of the Palaquium and Payena genera. - [general appearance, "feel," and distinctive ordor given when touched with, for example, a hot needle].
Hercynite (black spinel) - see Black minerals. I have a faceted hercynite from a Virginia locality that closely resembles polished jet. - [superior hardness].
Horn (stained black) - [lower luster than that of jet; gray streak; when touched with a hot point, emits an odor like that of burning hair].
Irish Bog Oak - “was apparently never meant to imitate, but can be confused with jet. It has a distinct visible wood structure, is dark brown in colour and is generally carved in Irish themes such as harps, shamrocks and castles.” (www.antiquejewelryonline.com)
Kimmeridge Shale - black bituminous shale from the Isle of Purbeck area of southern Dorsetshire, England. Although it appears that this shale has not been surreptitiously substituted for jet, some artifacts made from it resemble jet and have been so-designated in some collections. - [dull until smoothed and polished; texture].
Melanite (black andradite garnet) - see Black minerals.
Montana jet - obsidian from Yellowstone National Park; see next listing.
Obsidian - Black obsidian has been used in mourning jewelry. - [superior hardness].
Onyx (black portion) - black chalcedony. - [superior hardness].
***Paris jet - a name sometimes given “French jet” (q.v.).
***Plastics, Resins (e.g., epoxy) - [Appearance usually suffices.].
***Porcelain - black “jet porcelain” is sometimes fashioned into, for example, cabochons. - [superior hardness]
Sapropelic coal (jet-sapropelite) - a "jet" in some people's minds, including mine, but not according to the widely accepted, restrictive definition that specifies a wood precursor. Sapropelic coal "jet," which has no relict woody structures, is thought to have had algae as its precursor. In Russia -- where it occurs near, for example, Irkutsk, Siberia -- it has been fashioned into such things as long Turkish pipes, spoons, bowls, diverse carvings, and pieces of jewelry including hololith rings since at least the late 1800s (see, for example, Glushnev, 1995). - [exhibits no traces of woody structures; typically gives a light brown or yellowish streak].
Schorl (black tourmaline - also called jet stone) - see Black minerals.
Sphalerite - see Black minerals.
***Vauxhall glass – a name sometimes given “French jet” (q.v.).
***Vulcanite - see Ebonite.
Wood - examples are ebony and the so-to-speak partially fossilized bog oak of Ireland. - [lack of conchoidal fracture; without surficial coatings lower luster].
REFERENCES: Muller, 1987; see also Johnson, McClure & DeGhionno, 1996 re possible simulants.
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R. V. Dietrich © 2008
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