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1932Oatman Fire Agate (See Cuesta Fire Agate). The name Oatman Fire Agate is used in U.S. Bureau of Mines directory of gemstone producers (Austin and Copeland, 1995, p. 2).
1933O'Brion Canyon Agate, California?, ...varied patterns on bluish background, adv., Buck O'Brion, Lapidary Journal, v. 16, no. 1, p. 163. O'Brion Canyon does not appear in the U. S. Geological Survey geographic names data base and the name appears to be the creation of the advertizer. Berkholz (1962, locality 3) used the name OÆBrion canyon for surface materials collected from a fee locality a few miles from Horse Canyon that produced moss agate, lace agate and plume agate.
1934Occidental Agate, an archaic term possibly introduced by Bauer (1896, p. 506) for poorly marked, non-translucent agate, cf. oriental agate, which implies translucency.
1935Ocean Blue (Chalcedony), trade name, no locality, (Probably British Columbia, Canada), àblue green to blue gray, adv., Captain Joes, Lapidary Journal, v. 39, no. 10, p. 102.
1936Ocean Moss Agate, no locality, no description, adv., Hudson's, Lapidary Journal, v. 15, no. 3, p. 387.
1937Ocean Picture Rock., British Columbia?, ...scenes, ...translucent blues, greens, whites, adv., Capt. Joe=s, Lapidary Journal, v. 39, no. 9, p. 93. This material appears to be the same as Ocean Spray Picture Jasper (below). The earliest of these two names to be used has not yet been determined.
1938Ocean Spray Picture Jasper, no locality (probably British Columbian), ...ocean blue, ...scenic, ...white, brown, gray, adv., New Era Gems, Lapidary Journal, v. 39, no. 7, p. 92.
1939Ochil, of Rodgers (1973) = Rossie Ochil of Heddle (1901, p. 76). Macpherson (1989, p. 19) also mentioned this site.
1940Ochoco Agate, Oregon, see Ochoco Chalcedony, which name probably has priority.
1941Ochoco Brilliant Jaspers, Ochoco Mountains, central Oregon, ...reds, yellows, browns, unusual brilliance, adv., Herbert Wm. Lawson, Lapidary Journal, v. 3, no. 6, p. 464.
1942Ochoco Chalcedony, for Ochoco Mountains, Crook, Wheeler, Grant, and Josephine counties, Oregon. Gilchrist (1960, p. 62) stated that it was similar to Morrison Ranch materials and graded between jasper and agate. Probably similar to Ochoco Brilliant Jasper, above. See Rodgers (1976, p. 116-128).
1943Ochoco Eggs, for Ochoco area, central Oregon, generally carnelian thunder eggs. The Mineralogist, v. 21, no. 2, p. 96. These may be the same as Lucky Strike Thunder Eggs; the name Ochoco may have priority.
1944Ochoco jasper, well known jasper from Ochoco Lake, east of Prinveille, Oregon, that is found in thunder eggs. See McMullen (1975, p. 27). See Anon., 1954, The Mineralogist, v. 22, no. 11, p. 414.
1945Ochoco Mountains Jasper, Oregon, term used by Novinger (1969, p. 1530-1536); illustrated.
1946Ochoco National Forest Agate, for Ochoco National Forest, Oregon, usually white tubes, eyes in clear to, gray chalcedony matrix.
1947Ochoco Nodules, Ochoco National Forest, Oregon, ...carnelian to dark red, (Jackson, Q., 1953, p. 80, 81); no details, adv., C. G. and Marge Springer, The Mineralogist, v. 18, no. 4, p. 250. These may be the same as Lucky Strike Thunder Eggs and this name may have priority.
1948Ochoco Plume Agate, Oregon, patterns in pea green to olive green, for Ochoco Mountains, see Browning (1961, p. 240).
1949Ochoco Thunder Egg Beds, Ochoco National Forest, Oregon, adv., Herbert Wm. Lawson, The Mineralogist, v. 21, no. 6,7,8, p. 281. See also Zeitner (1979, p. 1260-1272).
1950Ochoco Thundereggs, synonym of Ochoco Thunder Eggs, appears in adv., Valley View Mining Claims, Lapidary Journal, v. 19, no. 1, p. 160. Rieman (1974, p. 1328-1335); Zeitner (1979, p. 1260-1272).
1951Ocotillo Geodes, near San Juanito?, Chihuahua, Mexico, thunder eggs with clear drusy quartz interiors. See Cross (1996, p. 112, fig. 77d).
1952Odessa Canyon Sagenite, California, àyellow, black banded and picture agates recorded by Berkholz (1962, locality 14) and Strong (1971, p. 42). Geographic Name Information System shows Odessa Canyon at 34o 56Æ 28ö N and 116o 51Æ 27ö W, San Bernardino county, California, Yermo Map, U.S. Geological Survey, 7.5Æ x 7.5Æ.
1953Ogilby (Calif.) Palm, agatized palm wood from Ogilby, California, area. Adv., Foster's Rock Shop, Lapidary Journal, v. 19, no. 1, p. 122.
1954Ohio Flint, Flint Ridge, Ohio. Colorful flints from several beds of marine units including the Vanport Limestone, Upper Mercer Flint in the Upper Mercer Limestone and in the lower Mercer and Boggs limestones of Pennsylvanian Age. See DeLong (1972). See also Anon (1968) and Zeitner (1960, p. 58-62; 1978, p. 2100-2110; 1973, p. 484-498), color illustration. The flint is mined from several privately owned fee sites and it forms Flint Ridge, 39o 59' 05" N and 82o 12' 35" W, Licking County, Ohio, Gratiot Map, U. S. Geological Survey, 7.5' x 7.5.'
1955Ohio Gem Flint, Flint Ridge, Ohio, see Ohio Flint.
1956Oil Agate, Point Reyes, California, name appeared on rocks-and-fossils news page on November 27, 1997. They were reported to be brownish translucent pieces with black specks and blobs. The notice was filed by See also Tarbaby Agate, rkp.
1957Ojitos Agate, Mexico, no description, adv., Shipley's Mineral House, Lapidary Journal, v. 13, no. 5, p. 683. Ojito translates to small eyes from the Spanish and this term describes an agate that is similar to and may be a synonym of Bean Agate.
1958Ojo Laguna Jasper, Mexico, sagenitic, adv., Rocky Joe's, Lapidary Journal, v. 18, no. 1, p. 172.
1959Oklahoma jasper, Oklahoma, no description, adv., Oklahoma Gem Crafters, Lapidary Journal, v. 8, no. 2, p. 189; Oklahoma Gemcrafters, Rocks and Minerals, v. 32, no. 1,2, p. 84.
1960Old Bed Priday [plume] cf. new bed Priday, term appears in adv., Herbert Wm. Lawson, The Mineralogist, v. 16, no. 12, p. 591.
1961Old Hell, California, agate producing site recorded by Strong (1966, p. 26, 27). The name does not appear in Geographic Names Information System.
1962Old Moulton, Texas, agatized wood,...adv., Dr. Edward Helpenstill, Rocks and Minerals, v. 32, no. 7,8, p. 442. ibid., Earth Science, v. 10, no. 4, p. 21; Lapidary Journal, v. 11, no. 2, p. 299
1963Old Paria, Utah, collecting area in southern Utah listed by Simpson (1975, p. 52, 53) on Paria River; pink and gray wood.
1964Old Ranch Jasp-Agate, red, white, yellow, and brown jasper found near Old Ranch off Clay Mine Road about 18 mi. E of Mohave, CA. The map provided by Shedenhelm (1974, p. 52) suggests the agate bearing deposits are in about sec. 34, T. 12 N., R. 40 E., Kern County, California, Boron Quadrangle, U.S. Geological Survey, 7.5 Minute Series (Topographic).
1965Ollie Agate, Iowa, see Burry (1979, p. 1312-1324). Probably marine sedimentary rocks from strata of Mississippian age. Name derived from Ollie, 41o11Æ53ö N and 92o06Æ30ö W, Keokuk County, Iowa, Ollie Map, U. S. geological Survey 7.5Æ x 7.5Æ.
1966Omineca Agate, British Columbia, red, crimson, and pink amygdaloidal agates from the vicinity of Francois Lake near Omineca and the Omineca Mountains. See Bell (1961, p. 240-241)
1967One-Day Jasper, the title of a magazine article by Schedenhelm (1972, p. 10) describing a field trip in Kern County, California, that could be made in one day, starting from the Los Angeles area. Not the name of a jasper.
1968Onion Skin Nodules, Arizona, near mile post 368, Highway 70, Hackberry entrance, McMackin (1976d, p. 2269-2309).
1969Onyx Agate, agate with straight layers, usually of contrasting colors, mostly from Brazil, Uruguay, see old descriptions. Bauer (1896, p. 512) described it as having milk-white cloudy bands that alternate with bands of another color, the two sets being sharply marked off from one another. See also riband agate, riband jasper.
1970Oolite, refers to spherical, accreted particle less than 2 mm in diameter. Often called petrified fish eggs, agatized fish eggs, etc. Adv., Gordon's Gem & Mineral Supplies, The Mineralogist, v. 17, no. 1, p. 45.
1971Oolite Agate (=Oolitic Agate)
1972Oolitic Agate, descriptive, agate with oolites, spherical particles that have grown by outside accretion and are less than 2 mm in diameter. See above. Many localities; material from Nebraska, South Dakota, and Wyoming have been observed and the term may be applied to any agate with oolites.
1973Oonachatae (See Ovoid-bearing agate).
1974Opal Butte Thunder Eggs, for Opal Butte, Heppner Oregon, cf. anon., 1963, The Lore of Thunder Eggs, Earth Science, v. 16, no. 3, p. 103. adv., Frank H. Waskey, Earth Science, v. 16, no. 4, p. 190
1975Opal Hill (fire agate), from approximately 114o 52' 30" W, 33o 27' 30" N, Riverside County, California, Thumb Peak Quadrangle, U. S. Geological Survey, 7.5 minute series (Topographic). Mitchell (1986, p. 22, 23).
1976Opalite, the term is usually applied to colored varieties of common opal according to the American Geological Institute=s Glossary of Geology.
1977Opalite, trade name and a term used for an opal simulant that appeared in adv., Aurora Chow & Co., Lapidary Journal, v. 39, no. 1, p. 145.
1978Opalite, Australia, see Australian Moss opalite, adv., Francis Hoover, Rocks and Minerals, v. 33, no. 5,6, p. 259.
1979Opalite Jasper, no locality, no description, adv., Oriental Crest, Lapidary Journal, v. 45, no. 1, p. 93.
1980Opalite, Mexico, adv., Crete Lapidary Supply company, Earth Science, v. 17, no. 2, p. 73
1981Opalite, Nevada?, Vincent Trescartes, Earth Science Digest, v. 1, no. 5, p. 30.
1982Opalized Agate, Australia, adv., Astro Minerals, Ltd., Lapidary Journal, v. 19, no. 12, p. 1326. àyellow, green, black dendrites, adv., Knowlton Associates, Lapidary Journal, v. 45, no. 2, p. 134.
1983Opalized Agate Nodules, Turkey, no description, adv., Murray American Corporation, Lapidary Journal, v. 30, no. 1, p. 39.
1984Opalized agate with dendrites, Turkey, adv., Murray American Corporation, Rocks and Minerals, v. 47, no. 6, p. 383.
1985Opalized Dendritic Agate, see opalized agate with dendrites.
1986Opalized diatomite, diatoms loosely cemented with opal, characterized by being chalky when wet and brittle when dry. Adv., Silver Star Specimens, The Mineralogist, v. 14, no. 5, p. 245.
1987Opal Mountain (?Opal), California, Hagar, D., 1946. A few California locations, Earth Science Digest, v. 1, no. 5, p. 8-9. Opal Mountain is situated at 35o 09Æ39ö N and 117o 11Æ 17ö W and prospects are in or near secs. 5, 6, 7, 8, T. 32 S., R. 45 E., San Bernardino County, California, Opal Mountain Quadrangle, U. S. Geological Survey, 7.5 minute series (Topographic). Moss agate and opal (Perry, 1961, p. 10). Berkholz (1962, locality 15) and Strong, (1971, p. 42, 44) recorded common opal, chalcedony and dendritic agates from this locality.
1988Opalo Andino, Trade Name (Andean Opal), a blue opal, no locality, adv., Monarch Jewelry & Gems, Lapidary Journal, v. 46, no. 2, p. 20. May be the same material that Zeitner (1992, p. 52-58) described as San Patricio Opal from Peru.
1989Opaque Black Wood, no locality, no description, ...adv., Keweenaw Agate Shop, The Mineralogist, v. 14, no. 9, p. 471.
1990Orange Swirl Agate, no locality, no description, adv., Aspen Lapidary, Rock & Gem, v. 3, no. 3, p. 85.
1991Orbicular jasper, generic term for jasper with randomly distributed, spherical or spherulitic inclusions. See also Shipley (1971, p.141)
1992Orbicular Jasper (Calif. Poppy Stone), from Paradise Valley or Llagas Creek. adv., Walkers Natural History Establishment, The Mineralogist, v. 5, no. 2, p. 25
1993Orbicular Jasper, California, (=Morgan Hill Jasper?), adv., Martin's Mineral Mart, The Mineralogist, v. 15, no. 1, p. 36.
1994Orbicular Jasper, Oregon, adv., Murray-American Corp., Rocks and Minerals, v. 38, no. 1,2, p. 86.
1995Orchid Agate, Utah?, ...lavender sheen, adv., Goldfield Gem, Lapidary Journal, v. 15, no. 1, p. 27. See Simpson (1975, p. 80, 81) and McMackin (1978a, p. 1316-1321).
1996Oregon Agate, Oregon?, no description, adv., Grieger's, Lapidary Journal, v. 19, no. 1, p. 212.
1997Oregon Beach Agates, Oregon, ...adv., Leo Stradley, Earth Science Digest, v. 1, no. 4, p. 33. See also: Newport Beach Agates, Yachats Beach Agates. See Rodgers (1976, p. 116-128).
1998Oregon Beach Water Agates (= enhydros), ...water bubble sealed inside, adv., Mrs. Agnes H. Rexsen, Lapidary Journal, v. 1, no. 1, p. 17.
1999Oregon Beach Stones, Oregon, probably Oregon Beach Agates, adv., W. S. Shirey, Lapidary Journal, v. 9, no. 6, p. 507.
2000Oregon Green Jasper, Oregon, adv., Rubey's Rocks, Earth Science, v. 17, no. 6, p. 282.
2001Oregonite, Oregon, an orbicular jasper according to Van Leunen (1945, p. 126). ...white eyes or rings in red jasper, adv., Smith's Agate Shop, The Mineralogist, v. 6 no. 4, p. 55. McMullen (1975, p.27) described and illustrated Oregonite as having circular light or dark spots that contrast sharply with matrix. The material may be oolitic or pisolitic.
2002Oregon Moss Agate, Oregon, adv., Southern Oregon Mineral Exchange, Earth Science Digest, v. 1, no. 5, p. 17.
2003Oregon Moss Agate - Priday's, adv., Gorham's Gem Shop, Earth Science Digest, v. 1, no. 6, p. 22; Lapidary Journal, v. 1, no. 1, p. 19.
2004Oregon Plume (Agate), Oregon, no description, adv., Charles Weidinger, Lapidary Journal, v. 7, no. 4, p. 311.
2005Oregon Plume Agate - Priday's, adv., Gorham's Gem Shop, Earth Science Digest, v. 1, no. 9, p. 27; Lapidary Journal, v. 1, no. 1, p. 19; ...Oregon, ...vein and plume agate, ...smoke and flame and carnelian plumes, adv., C. G. Springer, Lapidary Journal, v. 2, no. 1, p. 51.
2006Oregon Polka Dot Agate from the "Oolite Beds", no locality, no description, adv., Hortens Agate Shop, The Mineralogist, v. 6, no. 4, p. 102.
2007Oregon Polka-dot (=Priday Polka-dot?), white or light color with brown dots, adv., Gorham's Gem Shop, Lapidary Journal, v. 1, no. 1, p. 19. Earth Science Digest, v. 1, no. 6, p. 22.
2008Oregon Red Moss Agate, adv., Mary Ann Kasey, Earth Science Digest, v. 2, no. 2, p. 22
2009Oregon Sunset Agate, Richardson Ranch, Jefferson Co., Oregon. An advertizement in Lapidary Journal, (v. 16, no. 8, p. 736) ran by Mr. and Mrs. L.V. Bothwell, Gateway Route, Madras, Oregon, offers their ranch for sale and they state this property (first ranch north of Priday Ranch) is the source of this agate.
2010Oregon Sunset Jasper, may be synonym of Oregon Sunset Agate, above.
2011Oregon Tempskya, Oregon, no description, adv. Eldon Soper, Lapidary Journal, v. 5, no. 5, p. 359.
2012Oregon Trail Souvenir Agate, no locality,...moss, plumes, dendrites, sagenite, carnelian, and pastel, adv., Aldine Company, Lapidary Journal, v. 6, no. 3, p. 240. May be synonym of Sweetwater Agate as the Oregon Trail passed thru the region that includes the Sweetwater River, Wyoming.
2013Oricaria (viz.) Wood, California, no description, probably a misspelling of Araucaria (Norfolk Pine), adv., Edward H. & Nellie B. Combs, Lapidary Journal, v. 5, no. 4, p. 311.
2014Oriental Agate, archaic term that Shipley (1971, p. 142) refers to as a well marked and translucent agate. Fraser and Fraser (1988) suggested the term was used to imply higher quality than "occidental" agate, and this usage may go back to Bauer (1896, p. 506, 512) who said it was very translucent. Rossi and Procacci (1984, p. 73, fig. 12) illustrated a pale blue and white agate they called l=agata orientale.
2015Oriental Jasper, Van Leunen (1945, p. 126) suggested it is the same as bloodstone. See heliotrope or bloodstone.
2016Orocopia Agate, California, historic locality now on a military reservation Perry (1961, p. 312). The name is probably derived from Orocopia Canyon, 33o 32' 59" N and 115o 51' 34" W, Riverside County, California, Orocopia Canyon Quadrangle, U. S. Geological Survey, 7.5 minute series (Topographic). Strong (1972, p. 20-23) recorded bloodstone from this area.
2017Orphan Agate, term used by Schanafeldt, 1933, to describe any agate that has been removed from its original matrix by weathering and erosion and redeposited elsewhere.
2018Orsk jasper, a fine jasper from the southern Ural Mountains, Russia, recorded by Hintze (1915, p. 1492).
2019Osmundite nomen dubium, = opalized ferns, Zeitner, J. C., 1960. Rare gems of the midwest, Earth Science, v. 13, no. 2, p. 58-62. Illustrated and described as a silicified fern by McMullen (1975, p. 41). These probably are species of the fern genus Osmunda (see Tidwell, 1975, p. 124).
2020Otter Cove, Canada, Gotze, Plotze, Fuchs and Habermann (1999, p. 152, 153) suggested that agates from this site formed in a basalt and examined them by electron paramagnetic resonance, cathodoluminescence and trace element content.
2021Ovoid Bearing Agate, Heddle (1901, p. 71, 72) described chalcedonic and Cachalong ovoid forms in agates, and suggested they were a concretionary structure that formed when one of the agate forming components separated from another. These shapes had a fibrous structure that radiated from the center. These are similar to spherulitically crystallized oolites and/or pisolites described by Lebedev (1967, p.26-39). Heddle also suggested some ovoid structures were derived from disks (see disk bearing agate) of decreasing diameter were deposited one over another in an agate and this is similar to spherulites that formed as a result of splitting crystals. See also Oolites and Pisolites.
2022Owl eye agate, see Owl's Eye Agate
2023Owl's Eye Agate, Arizona, no description, adv., Roystons Rock Shop, Lapidary Journal, v. 28, no. 9, p. 1452.
2024Owl Head Mountains, California, local name?, locality for sagenitic agate recorded by Strong (1971, p. 26-28). The name Owl Head Mountains or any variation thereof does not appear in Geographic Names Information System
2025Owl Hole Sagenite, California, named for Owl Hole Mountains, P. Burnett, 1954, Earth Science, v. 7, no. 8, p. 13-15. Owl Hole Mountains do not appear in the U. S. Geological geographic names database, but Owl Hole Springs is used for a spring at 35o 38' 22" N and 116o 38' 52" W, San Bernardino County, California, and Burton (1954, p. 13-15) suggested Owl Hole was called Owl Hole Springs, and suggested the agates were similar to Wingate Pass materials which are seam agates.
2026Owl Lake, San Bernardino County, California, locality listed by Johnson (1971, p. 19). This may be the same locality as Owl Hole Springs, above. No further details available.
2027Owl's Head Agate, California, ...generally sagenitic agate (Perry, 1961, p. 310). This may be the same locality as Owl Hole Springs, above. No further details available.
2028Owyhee Blue Opal, (Oregon?), ...adv., Hap-Mark, Rocks and Minerals, no. 456, p. 487. ...deep blue, adv., Hap-Mark, Lapidary Journal, v. 23, no. 11, p. 1543. ...powder blue, adv., Hap-Mark, Lapidary Journal, v. 24, no. 7, p. 1014.
2029Owyhee Gem Picture Jasper (=Owyhee Gem Picture Rock), Owyhee Canyon, Idaho, adv., Stewart's Gem Shop, Earth Science, v. 21, no. 6, p. 281.
2030Owyhee Gem Picture Rock, Owyhee Canyon, Idaho, adv., Stewart's Gem Shop, Earth Science, v. 21, no. 4, p. 181
2031Owyhee Jasper, Oregon, ---a colorful and popular picture jasper that probably derives its name from the Owyhee River 43o 48Æ 46ö N and 117o 01Æ 28ö W and Owyhee Canyon that extends from 43o 12Æ 13ö N to 43o 44Æ 20ö N and 117o 37Æ 29ö to 117o 10Æ 45ö W, Malheur County, Oregon, Owyhee, Hole in the Ground, and Owyhee Dam maps, U. S. Geological Survey, 7.5 minute series (topographic). This material has been offered under several trade names including Owyhee Jasper Agate, Owyhee Junction Jasper, Owyhee Picture Jasper, Owyhee Picture Rock, etc. (see lexicon for more complete listing of synonyms).
2032Owyhee Jasper Agate, no locality (Oregon?), no description, adv., the Treasure Chest, Lapidary Journal, v. 26, no. 10, p. 1460.
2033Owyhee Junction jasper, Oregon, scenic, brown, tan, and cream color illustration, adv., Picture Jasper Outlet, Lapidary Journal, v. 33, no. 6, p. 1305. Fraser & Fraser (1989, p. 86) suggested that this is the same material as Owyhee jasper, but the color illustration and text in the above advertizement suggest it may lack the reds, blues, and greens of Owyhee jasper.
2034Owyhee Picture Jasper, Oregon, term used in adv., Stewart's Gem Shop, Lapidary Journal, v. 27, no. 11, p. 1705. Although the locality is listed as Oregon in the text of the advertizement, the heading suggests it comes from Idaho. See Owyhee jasper. Also, a synonym of Succor Creek Picture Rock, adv., Walla Walla College Equipment Fund, Lapidary Journal, v. 28, no. 8, p. 1225. If these names are synonyms, it will have to be determined which name came first, Owyhee or Succor Creek, to resolve the nomenclatural issue. Classic blue, Heritage Brown, and Scenic Green are variety names used by Murray American Corporation, Lapidary Journal, v. 31, no. 3, p. 775. See also Zeitner (1984, p. 776-782).
2035Owyhee Picture Rock, Idaho, adv., Stewarts Gem Shop, Earth Science, v. 12, no. 3, p. 102.
2036Owyhee Picture Rock Jasper, Oregon?, adv., Murray American Corporation, Lapidary Journal, v. 31, no. 1, p. 76-77.
2037Owyhee Plume Agate, Idaho, material recorded by Robertson (1975, p. 16-21).
2038Oxblood Jasper, Africa,, red, adv., Riviera Lapidary Center, Lapidary Journal, v. 38, no. 12, p. 1561. Probably the same material as Ox Blood Jasper, below.
2039Ox Blood Jasper, South Africa?, ...blood red, adv., Riviera Lapidary Center, Lapidary Journal, v. 31, no. 9, p. 2013. Riviera advertized Africa Oxblood Jasper, ibid., v. 39, no. 10, p. 77 and suggested the source was in Africa.
2040Ozark banded agate, Missouri, from an area about 75 mi. SW of St Louis?. NFI. Kissick, R., 1956. A new Missouri locality, The Mineralogist, v. 24, no. 5, p. 216.
2041Ozark Blue and Brown Chalcedony, Arkansas?, red jasper, calcite, onyx, adv., John Jennings, Hobbies, v. 46, no. 12, p. 112.
2042Ozarkite?, no locality, no description, mis-rendering of Mozarkite?, adv., Aleta's Rock Shop, Lapidary Journal, v. 19, no. 1, p. 52. Carpenter (1963, p. 117) applied the name to colorful cherts from Lincoln and Benton Counties, Missouri.
3069Opalite: From Donald Kasper (personal communication, 2006) Opalite is an opalized volcanic tuff or ash that may occur with common opal and agate. It may be dendritic. The key distinction between opalite and common opal is that opalite is very hard; specimens of opalite saw or chip with difficulty, whereas opal is commonly glassy and chips easily Opalite may have a wet appearance upon breaking fresh specimens creating the illusion of opal. Because of its hardness, opalite will commonly be found in pronounced outcrops or ridges in localities in the Mojave Desert and other world wide localities, while common opal outcrops form muddy, rolling hills or colored soil (laterites?). Common opal fractures readily into tiny crumbs upon hitting with a rock hammer and opalite does not. Opalite probably has a hardness of five to six, and common opal has a hardness of probably two. Opalite appears to decompose into sand, while common opal appears to decompose into a clay or mud (expansive clay). Opalite is associated with deep beds of volcanic ash or welded ash flow tuff, so it may occur with deposits of fossil palm root, palm wood, and bog in the Mojave Desert region. Opalite is often associated with moss agate and plume agate. Opalite can be a variety of colors, including white, tan, brown, green, and peach. Opal has a brittle fracture to it, while opalite does not exhibit this property. It is difficult to test hardness because of variability of specimens. Kramer (California) opalite specimens appear to be able to scratch Opal Mountain. opal specimens, but just barely. A knife can scrath the opal, but not opalite, but I (Kasper) do not know if this will be consistent (Knives are supposed to be Mohs hardness 5.5). However, the Kramer specimen is jasperized as a bog, so it could be harder from that. It's appears that opalite is H 6+ and Opal is H 5+. When some say opalite is "massive common opal", I (Kasper) think they are refering to its strength achieved through combination with tuff and subsequent loss of brittleness. Subsequent literature search shows that opalite occurs in the Ogallala Formation of Pliocene age in the North American mid-continent with extensive deposits being found in South Dakota, Nebraska, Wyoming, Kansas, Oklahoma, and Texas. The opalite from Kansas has been offered as moss agate for over 100 years, first being reported by Kunz (1885) from deposits in Graham County. Opalite also occurs in Australia and material from there has been offered as “Golden Moss Opalite” and “Blue Moss Opalite” in the gem trade. Common dendritic opal has been mined from deposits in the Ogallala Formation near Angora in Box Butte County, Nebraska. There, the common opal occurred in small individual nodules as opposed to thickly bedded or ledge forming deposits of opalite.

About the Agate Lexicon

The Agate Lexicon and glossary of amorphous and cryptocrystalline silica gems have been designed to be used in conjunction with the Agate Bibliography, which was compiled to be used by researchers, hobbyists, historians, lapidaries and other individuals which have an interest in these stones. Numerous localities are listed here but this does not imply that the sites are available for collectors or collecting. Many of the sites are historic, depleted, are on private property or are protected by legal leases or claims and some are now on protected sites such as parks, nature preserves, or historic areas. Wherever possible, stratigraphic details are listed, but the user must always refer back to the original citations. Map information has been derived from 7.5' x 7.5' topographic maps issued by the U.S. Geological Survey (USGS) and latitude and longitude have been derived mostly from Geographic Names Information System of the USGS.

Authors should not cite the Agate Bibliography or Agate Lexicon as a source in their published or unpublished works but should cite only those publications listed therein.

Named varieties of agates, jaspers, etc., have created special problems for both scientific researchers and historians. We have recognized at least two different usages of names. Some names appear to have geologic / historic validity, as they were described along with the lithology / geography of a region. Some names were introduced simply as trade names to boost sales of gem dealers. In the former case, the name will be followed by appropriate literary citation as to who first used the name and in what context. In the latter case, an advertisement (abbreviated adv.) is the first published record or public notice. We have tried to find the earliest citation in either case and the user should keep in mind that older citations unknown to us may exist. Advertisements are not cited to generate business but to simply give a historic source; many of the firms appearing in the citations are indeed no longer in existence.

Cited materials are generally only from accessible sources such as professional journals, magazines, hobbyist journals, open file reports of government agencies, newspapers, etc. Bulletins issued by local clubs and societies are generally not cited with the exception of those special publications that were actually made for public distribution.

Wherever possible, imagery of one or more specimens of named agate varieties, structures, patterns, etc. are provided. Images have been provided by several sources and are not to be utilized in other pages without the consent of the image owner.