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Fine Art Mosaics With Agates and Fossils and Beads

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AGATE

(Fr- agate; Ger- Achat; Nor- agat; Rus- )

AGATE , SiO2. (Encounter also CHALCEDONY , ONYX and THUNDER EGG entries.)


A. Agate, polished surface of a Lake Superior agate (width  ~ 8 cm) from Keweenaw Point, Michigan.  Specimen collected, cut and polished by Robert J. Barron.  Seaman Museum, Michigan Technological Academy.  (© photo past John Jaszczak )

B. Fire Agate ( greater dimension - 2.i cm ) from Deer Creek, Arizona.  Rincon Mineral Co. ( © photograph past Jeffrey A. Scovil )

C. Iris agate (width - 9 cm) from Patagonia, Argentine republic.  St. Paul Gems & Minerals. (© photo by Jeffrey A. Scovil)

D. Agate mouse (height - ca. 6 cm) carved by Gerd Dreher.  Silverhorn. (© photo by Jeffrey A. Scovil)

E. "Joshua tree agate" (width - half-dozen.4 cm).  Jimmy Vacek collection. (© photo by Jeffrey A. Scovil)

F. Moss agate cabochon (greater dimension - 4.viii cm) from Bharat.  Zeolites Republic of india. (© photo by Jeffrey A. Scovil)

K. Agate (width - 28.4 cm) from Rio Grande exercise Sul, Brazil, that has been dyed with diverse hues.  Frederick H. Pough collection. (© photograph by Jeffrey A. Scovil)

H. Agate from Idar-Oberstein, Germany -- run into photograph, full caption and related text  under REMARKS subheading.

[See also Figures 51-59 and AppB1-AppB10 in the MIMETOLITH file on this web site.]

Clarification: Primarily, agate is conspicuously banded chalcedony;  the bands range from parallel to highly uneven, fifty-fifty inside some  individual specimens.  Both color and calorie-free transmission commonly differ from band to ring.  In addition, chalcedony with variously shaped splotchy areas, commonly having arborescent shapes are called agate, usually moss agate.
Colors - reddish brown, yellowish chocolate-brown, greenish (rare), bluish (rare), purplish, white (including milky and bluish white), greyness, green gray, black, and brown
H. 6½-7
South.G. 2.59-2.67
Lite transmission - transparent to subtranslucent (cf. jasper)
Luster - waxy
Breakage - subconchoidal fracture yielding fine granular appearing surfaces
     Miscellaneous - usually triboluminescent.

OTHER NAMES: Several names accept been introduced.  M ost consist of adjectives based on feature features, localities or fancies plus agate -- east.g., burn agate. In addition, agate and agatized have been applied, admitting inappropriately, to largely chalcedony materials that are neither banded nor moss agate. Pabian (2002) lists what he calls "2,943 [updated as of 3/12/'01 to iii,084] named varieties," which, as noted in the lexicon, actually includes names given "Agate, Jasper, Opal and other Amorphous, Cryptocrystalline, or Spherulitic Forms of Gem Silicon Dioxide."  In any example, many terms take been given diverse agates, especially in  rock shops and advertisements.  And, in my stance, almost of these terms seem sick-conceived.  Examples of names, most of which have been circulated r elatively widely, follow:
  • Aggos - marketplace name given thin slices of agates from the Yellowstone River area of eastern Montana that take been  honed to give them satin -- i.east., low matte-like, rather than polished -- surfaces.  Lapidaries think such surfaces amend showroom the agates' patterns and colors than polished surfaces exercise (Johnson et al., 1999, p.210).
  • Amberine - xanthous greenish agate from Death Valley, California.
  • Blood agate - blood-cherry-red, pinkish or salmon colored agate from Utah.  (cf. pigeon blood agate.)
  • Brecciated agate - breccia the larger fragments of which are agate: The names mosaic agate and ruin agate have also been given to some fractured and rehealed agate.
  • Cloud agate - calorie-free greyness and off-white chalcedony with an overall design that roughly resembles clouds.  Examples I have seen practice not appear to fit whatever widely accepted definition of agate;  externally, the masses I have seen  resemble thunder eggs.
  • Conachatae - agate with "inclusions of cacholong opal arranged as conic patches" (Mitchell, 1985).
  • Condor agate - trade proper noun for a rather "colorful [agate], good reds and browns, etc. ... from Patagonia" (Pough, personal communication, 1998).
  • "Coral sea" agate - trade proper name for a doublet of lace agate atop reconsituted turquoise (Overton, 2012).
  • Dentritic agate - agate with inclusions or coatings of dendrites.  See also moss agate on this list.
  • Dot agate - overall term given chalcedony that contains spheroids that announced as spots on plane surfaces;  see also Polka-dot agate on this list and St. Stephen'southward Rock under the OTHER NAMES subheading in the CHALCEDONY entry.
  • Eye agate - agate with alternating, concentric color bands. The terms orbicular agate and Aleppo rock accept as well been applied to these agates, and agates with two "eyes" have been referred to every bit oxeye and owl-eye agatedue south. (cf. band agate.)  Many agates marketed as middle agate exhibit their "optics" -- i.e., the concentric banding -- only because they have roughly spheroidal tops the diameters of which are perpendicular to the banding of the normal sparse-banded agate rough from which they were fashioned;  this fact is quite apparent when ane examines agate marbles (run across, for example, www.marblealan.com/nonglass.).
  • Fancy agate - term sometimes applied to agates exhibiting unusually intricate patterns.
  • Fire agate (sometimes referred to as iridescent agate or rainbow agate) - to some people, this is a non-agate variety of chalcedony;  although it might be argued that its agate designation may have been based on the layered arrangement of the inclusions responsible for its iridescence, information technology seems more probable it was so-named as a marketplace ploy.  In whatsoever case, every bit the name suggests, some people see its overall appearance as resembling called-for embers.  It is multicolored -- e.g., fine quality stones exhibit various combinations of red, violet, orange, green, yellow and brownish hues.  Every bit examples of fire agate localities, Sweaney (1979) mentions occurrences inside the Sonora Desert region of northern Mexico and southern Arizona (e.g., on Saddle Mountain, most Tonopah, Maricopa County and near Safford, Graham County) and also from the Primal Basin of Mexico.
  • Flame agate - Two quite dissimilar agates have been chosen flame agate in the literature.  Johnson and Koivula (1998) review and present fine illustrations of both. The following, with pertinent quotations from Johnson and Koivula (i.e., not directely from Sinkankas and Macpherson) briefly draw the appearances of these agates.

    ane. John Sinkankas (1959) described flame agate as a "highly translucent, colorless agate with few typical agate bands, simply rather containing long streaks or 'flames' of a bright red color" (see Johnson and Koivula, op cit., Figs. four and 5). The textile he described came from Villa Ahumada, Chihuahua, Mexico.

    2. H.G. Macpherson (1989) practical the term flame agate to an "agate of any color in which the pattern resembles a candle flame" (see Johnson and Koivula, op cit.,  Fig. three).  Many agates from many worldwide localities, if correctly fashioned, could be designated as flame agate under this definition.

  • Fortification agate - agate with bands that resemble bastions (etc.) of ancient forts -- cf. riband agate and ruin agate. Noteworthy fortification agate has been collected from Fourth of July Tiptop, almost Hassayampa, Maricopa County, Arizona.
  • Frost stone (or frost agate) - translucent grayness chalcedony that contains desultory snowflake-like masses.  A noteworthy occurrence is in the Mojave Desert of California.
  • Hokkaido agate - overall "brown to grayness nodular stone ... from the northernmost ... Japanese Islands.  The eye of the stone has abrupt fortification banding that blends into rounded bull's-eye banding around the outer protions... usually dyed to resemble [reddish to cinnamon-brown] carnelian ( Messchæ rt ,1966-67).
  • Iris agate - agate with extremely sparse bands that apparently diffract light rays, like a diffraction grating does, thus exhibiting colors of the spectrum.  Iris agates take been recorded from several places in California; the vicinity of Challis, Custer County, Idaho; virtually Crimson Hill, Caron Canton, New United mexican states; at Antelope, Waco Canton, Oregon; and along the banks of Yellowstone River, Montana.
  • "Japanese jade" - name sometimes given "an opaque, nonvitreous, milky-white agate with spinach-dark-green splotches ( Messchæ rt , 1966-67).
  • Jasp agate (agate jasper, jasp fleuri, and jasponyx) - proper name sometimes given textile that is considered either 1. intermediate betwixt jasper and agate;   or  two.to consist of bands of transparent chalcedony and subtranslucent jasper.
  • Lace agate - translucent blueish and white banded chalcedony;  lace agate that resembles moonstone is referred to as blue lace agate in some marketplace outlets.  Three source areas are Majestic County, California, the Balmorhea area of Texas and Namibia (formerly S West Africa).  Also, a crazy lace agate has been recorded from several localities in the state of Chihuahua, Mexico.
  • Laguna agate - trade proper noun for "a very colorful Mexican agate" (Pough, personal communication, 1998) from, for instance, Eijido Ojo Laguna, Chihuahua, Mexico.
  • Lake Superior agate - name frequently given to agates found within upper Midwestern U.Due south. traprock masses of, for example,  Michigan's Keweenaw Peninsula  and in unconsolidated beach and glacial deposits derived from those rocks (Robinson, 2001). See too Shadow agate.
  • Lantana - name broadly applied to banded agate, chalcedony and jasper plant every bit chaplet produced in Ilorin, Nigeria during the 19th and 20th centuries (Lui, 1995).
  • Mosaic agate - meet Brecciated agate.  Unfortunately this term has also been applied to some brecciated "Mexican onyx" (see TRAVERTINE entry).
  • Moss agate (Mocha stone or mocha stone) - subtransparent to subtranslucent, white, calorie-free greyness, yellow or greenish agate with greenish and/or brownish to about carmine atomic number 26 oxide and/or black manganese oxide arborescent inclusions that resemble moss, trees and/or landscapes. Historically, this designation moss agate has evolved as follows:  i.Appatently information technology was originally applied to chalcedony with dark-green dendritic inclusions.  2.Later on, information technology was  extended to include chalcedony with reddish dendritic inclusions.  three.Later on, information technology was extended further to include chalcedony with black dendrites, such as that previously chosen Montana agate. [and]  four. Today, most, if of not all, chalcedony with any of these kinds of inclusions is widely referred to as moss agate.  Some agates of this genre, yet, have been given additional adjectival modifiers that pertain to whatsoever their forms are idea to resemble -- e.g., bouquet, dendritic, blossom, Indian, landscape, mosquito, painted, breathtaking, seaweed, tree, and even the less attractive adjectives gnat, midge and mosquito.  Diverse moss agates accept long been associated with Hindustan;  Yellowstone National Park, Wyoming; and the bed of the Yellowstone River in Montana -- due east.g., almost Glendive, Dawson County, Montana.
  • Mushroom agate   - cabochons, beads and pendants take been marketed widely as as mushroom agate, mushroom jasper and mushroom rhyolite, which is said to have been metamorphosed.  All, if indeed three differently constituted ones be, are said to come from Arizona.  I have seen just photographs of whatsoever of these, and  all appear to be near the aforementioned material.  In any case, the photographs do exhibit patterns that resemble mushrooms on polished surfaces.
  • Occidental agate - term sometimes practical to low quality agate.
  • Onyx (also onyx agate) - strictly speaking, coarsely banded agate -- run into CHALCEDONY and ONYX entries.
  • Pagoda stone - agate characterized by images that resemble pagodas.  Unfortunately, this designation has also been applied to other rocks and resin replicas of some of them that roughly resemble multi-story pagodas -- e.m., sure fossiliferous limestones (meet MARBLE entry); differentially weathered sparse-layered rocks, such equally interlayered fe-rich and then-to-speak iron-free sandstones;  and and so-chosen "stacked towers" of relatively flat stones.   In addition, a multifariousness of jade (q.5.)  and the agalmatolite (meet APPENDIX A), which is used in China for carving pagodas etc., are oftentimes called pagodaite.
  • Palm root agate - come across FOSSILIFEROUS ROCKS entry.
  • Pigeon blood agate - deep red and white agate from Cisco, Utah.
  • Plume agate - a special kind of moss agate virtually of which consists largely of most colorless or low-cal-colored, commonly blueish, agate with included  sporadic red, xanthous, yellowish brown or violet fluffy-appearing masses, some of which resemble egret plumes. The "plumes" of these agates from a number of unlike localities have been variously said to consist of or pigmented by goethite, various manganese oxides or combinations thereof, realgar and/or orpiment. Some especially well-studied plumage agate occurs inside  thunder eggs of Saguache County, Colorado (Kile, 2002, and come across figure A in THUNDER EGG entry). Other fine examples have been collected near Prineville, Cheat County, Oregon and s of Tall, Brewster County, Texas.
  • Polka dot agate - a translucent moss agate with pocket-size red, yellow or brown included masses that lend a polka dot appearance, especially on polished relatively flat surfaces.
  • Pom pom agate - agate containing pufflike clusters.
  • Riband agate (also chosen ribbon agate) - agate with relatively broad bands.
  • Band agate - agate exhibiting concentric color bands -- cf. eye agate.   In addition, withal, the term "ring agate" is frequently used in the market to refer to whatsoever agate that is set in whatever ring (finger, ear, etc.).
  • Rogueite - milky white moss agate with green inclusions from the Rogue River valley of southwestern Oregon.
  • Ruin agate - name applied variously to, for example, landscape agate that resembles ancient ruins and to brecciated agate.
  • Saginitic agate - name practical to agates characterized as including "acicular, or needle-like, mineral growths" (encounter illustrations in McMahon, 1999).
  • Shadow agate - agates of the Lake Superior region whose apartment, polished surfaces appear wavy or to have shadowed areas, some of which take been termed "black holes."  Sukow (1999) offers an hypothesis to account for this feature, and indicates how one might spot this issue in raw material.
  • Shell agate - misnomer applied to silicified mollusc shells -- run across Turritella agate in FOSSILIFEROUS ROCKS entry.
  • Snake skin agate - term applied to both silicified corals and chalcedony nodules whose surfaces roughly resemble the scaly pattern of some snakes' skins -- see FOSSILIFEROUS ROCKS entry.
  • Star agate - agate that exhibits roughly star-shaped forms.
  • Swiss lapis - marketplace name given to some agate that has been dyed bluish to resemble lapis lazuli.
  • Topographic agate - agate exhibiting lines that resemble contour lines on topographic maps.
  • Vistaite - name given to moss agate and likewise to some of the jasper from the vicinity of Prineville, Cheat County, Oregon.
  • Woods agate - silicified wood that exhibits agatelike banding. Unfortunately, this term has as well been applied, albeit incorrectly, to some silicified forest that is chalcedony and/or jasper with no banding like to that which is feature of agate.
  • Zigzag agate - agate, the polished surfaces of which exhibit a pattern of zigzag lines.

USES: Jewelry, buttons, alphabetic character openers, handles for cutlery, paper weights, bookends, picture frames, giutar picks, bowls, coasters, etc.  Loftier quality cameos and intaglios and other engravings fashioned from agate (run across besides ONYX entry) have been used in such various pieces every bit earrings, brooches, pendants, plaques and tietacks -- meet the fine example pictured on the cover of the spring issue of Gems & Gemology, volume xix.  One of the most interesting pieces fashioned from agate that I know about is the head of a Scepter from Cyprus, now in the Metropolitan Museum of Art at New York City.

An agate tool found beneath volcan ash erupted from Mount St. Helens ~15,800 ago appears to back up the existence of humans more ancient than the Clovis civilisation, which is oftentimes been cited as the oldest human group of the western United states.  This tool, which has been found to have claret residue of an extinct Bison on information technology, is said to be a product of the University of Oregon's archaeolotical field studies. (Bodman, 2015)

Eye agates, especially those with dark centers, were used for the eyes in carvings of idols, especially in aboriginal Egypt.

Spendlove (1979) illustrates agates – e.thousand., ruin agates – upon which fine art work has been painted.  Painters have also used other agates as backgrounds for their paintings.

Chalcedony, specially agate, has been used along with other gemrocks, such as lapis lazuli, malachite and rhodochrosite, in the production of intarsias (i.e., gemstone inlays) since at least the late17th century. In add-on, dendritic agates have been incorporated in doublets in jewelry -- e.g., "Coral sea" agate (q.five.) -- and as well as "discs framed inside of other jewel materials such as rock crystal, jasper, chrysoprase, obsidian, tiger'due south-middle, and banded agate" (Overlin, 2011) and elsewise ( ibid ) .

Two other uses of agates, not as a gemrock but of possible practicable involvement, are for the production of mortars and pestles and the fulcrums for balances.

Perhaps 1 of the best known uses of agate, especially in the past but persisting today, is every bit the minor spheres used for "shooting marbles." Indeed, some people phone call marbles (mibs) -- including those non made of agate -- "agates."

OCCURRENCES: Agates most commonly occur every bit crenel fillings (nodules) in consolidated basaltic magmas and in detrital textile (e.g., alluvium, embankment gravels and glacial deposits) derived from those rocks. Noteworthy quantities also occur as so-called replacement fossils -- due east.g., agatized wood.

NOTEWORTHY LOCALITIES: Much of the color-banded agate of the market has come from a roughly chugalug-shaped region that extends from near Salto, in eastern Argentina, to near Porto Alegre, Rio Grande practise Sun, southern Brazil.  Noteworthy quantities take also come from the Deccan "trap rocks" (i.e., basaltic rocks) of Republic of india;  from a number of regions in China;  and from the Agate Creek area of North Queensland, Australia.  Several diverse kinds of agates have been found at literally scores of localities in Northward America -- encounter, for instance, those noted in the manufactures in the book compiled and edited by Leiper (1966). Meet also those noted after some of the agates listed under the OTHER NAMES subheading. Some of the agates that occur as amygdules inside or that have been weathered out of  "Lake Superior meta-basalts" in northwestern Michigan are of particular interest because of their inclusions of diverse minerals.  These minerals, which occur either individually, paired, etc., are well described and illustrated past Rosemeyer (2012).  The minerals that occur are native copper (apparently near common), chamosite, epidote,  hematite, cuprite, and prehnite and calcite (ibid.).
Agates with diverse patterns, which are recorded as consisting of "3 silica phases: depression-a quartz, moganite [non-approved term] and opal-CT,"  and occur within Triassic "basaltoids" in Sidi Rahal of the Morocco Atlas mountains are described and illustrated by Dumanska-Slowik et al., 2014.Another possible locality(?):  David Livingstone, the famous Scottish missionary and African explorer who discovered Victoria Falls in 1855, wrote (1865), "The ground is strewn with agates for a number of miles higher up the falls."  According to data Craig Gibson (personal communications and enclosures sent 2005) agate amygdules practice occur in basaltic lavas that crop out at Victoria Falls;  however, he also notes, "I have never heard of the agates from the Falls expanse being used in any commercial manner and I am sure that if they had been that would have been mentioned in the literature." REMARKS:Theophrastus in his well-known On Stones  (ca. 315 B.C.) indicates that the designation agate was based on the source of such stones from the Achates (now Drillo) River in southwestern Sicily , which, by the way, is still a source of agate and chalcedony.  Be that as information technology may, between 3000 and 2300 B.C., Sumerains (and apparently fifty-fifty earlier, Babylonians) fashioned agate into axe heads, some of simply ceremonial use.

Many color-banded agates of the marketplace take been dyed.  Indeed, agate tin be dyed well-nigh any color or black by soaking it in various chemical solutions (see Fig. G). (It is surprising that someone has not differentially dyed, for example, fortification or ruin agates, to distinquish what might be interpreted as footing versus sky, etc. -- Perhaps someone has and I have just non seem the results.)  In addition, heat treatments have been used -- both alone and along with, for example, immersion in certain chemicals -- to change agates' colors.

Agate per se has long been reputed to prevent or assistance cure all sorts of disorders -- e.g., to prevent insomnia and even as a follow-upwards to promote pleasant dreams.  In improver, agate has been said to make people more persuasive and less disagreeable.  As well, center agate amulets have been, and in some places continue to be, attributed the power of curing peel diseases; but, elsewhere their "stock-still stare" is said to have raised all kinds of reprehensible reactions, including those associated with the proverbial "evil eye."  In add-on, moss agate also has been given several health-related attributes, especially those related to people's eyes and mouths.  --  A list of legends associated with agate could go on and on ... and on.  The following lines of poetry virtually moss agate, said to take been written in the 4th century A.D. (King, 1865), serve, I think, every bit a fitting endmost for this paragraph:

"Carrying the Tree-Rock with thee to the shrine,
Thou shalt propitiate each power divine.
The gem the semblance of a garden shows,
Where growing trees entwine their leafy boughs;
Hence a fit title bears it with the wise
Who the Tree-Agate is a treasure prize:
1 function displays the perfect Agate-rock,
In one a shaggy grove is patently shown."


H. Agate slice (greater dimension - 13 cm) from Baumholder, near Idar-Oberstein, Rhineland-Palatinate, Germany -- see the following paragraph for additional information. Donald Gabriel Collection (DCG 355) in Seaman Museum, Michigan Technological University.  (© photo by George Robinson)

A gates, in lava flows in the vicinity of Idar-Oberstein, southwestern Germany, served to initiate the stone cutting industry that led to these towns' becoming one of the globe's largest centers for cutting and polishing colored stones.  Foshag (1953) notes that "The Idar-Oberstein agate is a distinctive blazon .... Information technology is, generally, more colorful than agates from other areas; many show a rich, reddish color delicately mottled or spotted. Other types show a sharp narrow zoning of dense layers. A mutual feature is an outer zone of dense, finely banded agate with a central filling of crystalline quartz or amethyst. Although many small amygdules of agate tin can be seen in the basalt cliffs [of the area], pieces of usable size were and are now extremely rare."  George Robinson (personal communication, September, 2004) notes of the specimen shown as "H": "Its colors are incredible (and natural!) and it is perhaps the finest agate in our [theSeaman Museum] collection."


I. Agate piece (greater dimension - ~ix cm) from vicinity of Idar-Oberstein, Rhineland-Palatinate, Deutschland -- see the preceding  paragraph for boosted information. These two photographs, which are polished sides of the same NODULE, once part of the Custer [ i.e., General George A. Custer (1839-1876) ] family collection, is currently owned past Carl Gruber.  Carl notes that when he visited the Idar Oberstein museum, he took his specimen, showed it to them, and  "They had a very like specimen and were shocked to see mine, since no others of similar quality had turned up.  [AND,]  Tthey said information technology had been mined in the late 1800's nearby." (© photos courtesy of C. Gruber)

Agate was apparently the start stone in Aaron's breastplate (come across GLOSSARY) and is thought past some scholars to have occupied position number nine in High Priests' breastplates.   Agate is considered by some people to be the birthstone for June, and by others to relate to the zodiac symbol Gemini (May 21 - June 21).

A rather interesting aspect of recovery of dendritic agates in key India is reported by Weldon (2008):  "Miners work the riverbed twice a year during the region'due south dry seasons.  One unusual arroyo taken by local miners is to plant cucumbers and other deep-rooting vines in the riverbed, where the fast-growing roots reportedly loosen the soft alluvium, causing many nodules to rise to the surface.  These are then easily collected for cutting."

The Fairburn agate, also called fairburnite is the official state gemstone of South Dakota ;  individual specimens of these agates, which are fine examples of fortification and riband agates, occur sporadically in gravels in the Black Hills of Due south Dakota (Clark, R.West., 1998).  Agate referred to as Lake Superior or Duluth agate in Minnesota, and sometimes called Keweenaw or Isle Royale agate in Michigan, is the official state gemstone of Minnesota.  Blue agate (I have been told, merely have not been able to ostend this, that chalcedony is what really has this stardom.) and Prairie agate are, respectively, Nebraska's official state gem and state rock. Agate found in gravel is the country gemstone of Louisiana.  Agate, otherwise not specified, is one of 2 state gemstones of Montana. Agatized coral is the state stone of Florida.

SIMULANTS:

***Agate ware - Wedgwood china made to roughly resemble agate. - [Appearance is sufficient to distinguish this material from agate.].

Brecciated travertine - this gemrock is sometimes marketed as mosaic agate. - [inferior hardness].

***Ceramic ware with enclosed horsehair --e.g., some fair ceramic bowls (etc.), whose clay forerunner had horsehair added to it prior to its being fired, that roughly resemble moss agate.  I have seen only photographs of these advertized as having been made by "Acoma Pueblo artists." - [Advent suffices to distinguish this material from moss agate.].

***Drinking glass - Marilyn Jobe of Ellenton, Florida has produced glass, fashioned equally beads and cabochons, that closely resembles agate - [inferior hardness (H. ~ v)].

Imposed (etc.) dendrites  -  1.a somewhat complicated procedure has been used to produce native copper dendrites on chalcedony (Koivula, 1986, p.246);    2.the dendritic inclusions of some plume agates have been produced by electrically stimulated chemical atmospheric precipitation and thence incorporated as parts of assembled stones;  [and]  3.a chalcedony cabochon with a dendritic-shaped design painted on it to give it a moss agate advent has been recorded (Kane, 1988).

***Plastic - a photograph of a "plastic false simulating agate" is shown by Nassau (1974). - [inferior hardness (H. < 5)].

Royal agate - term sometimes given to mottled obsidian. - [inferior hardness (H. five-5½)].

***Stratified Pyrex - pyrex drinking glass with layers of more than than one color. - [inferior hardness (H. ~ 5)].

Whale molar (dyed) - some beads of this textile closely resemble agate; Liu (1994, p.74) illustrates a couple of these beads that accept been termed "crane's crest" - [texture and inferior hardness (H. ~ iii)].

REFERENCES: Cross, 1998;  Dake, Fleecer and Wilson, 1938;  Frondel, 1962;  Leiper, 1966;  Macpherson, 1989.  (For information re dendrites, see Potter and Rossman, 1979A). Rocks & Minerals -- Vol. 89, No.iv includes a number of well illustrated manufactures nearly agates -- due east.g., those from southeastern Utah and Keweenaw Canton, Michigan -- equally well as an article virtually some thinsections of agates from localities in, for example, Brazil and France, AND an brusk feature about an artist'southward depiction of agates.

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