"Turritella" Agate

Despite its name, “Turritella agate” is not made of fossil snails of the genus Turritella. This has been realized by professionals and many amateurs for a long time, but the name (and the confusion it promotes) have persisted. The snails are actually properly refereed to as Elimia tenera, in the family Pleuroceridae. The rock in which they are so abundant varies from a soft sandstone to a dense chalcedony. It is this dense silicified rock that is so popular with gem and mineral hobbyists, and also (unfortunately) with purveyors of "new age" ideas of crystal healing and the like.

Elimia agate comes from the Green River Formation in southwestern Wyoming, northeastern Utah, and northwestern Colorado, from layers deposited in an series of ancient lakes that geologists call Lake Gosiute and Lake Uinta, in the early and middle parts of the Eocene Epoch, between around 53 and 42 million years ago. These rocks, in other words, formed in fresh water. The real Turritella is a group of snails that live only in the ocean. The shells of Elimia are distinguishable from real Turritella by being generally shorter and wider, but especially in having axial as well as spiral sculpture on the shell.

 

A Bibliography on "Turritella" agate

I. Biology of Elimia (=Goniobasis)

Burch, J.B., 1989, North American freshwater snails. Malacological Publications, Hamburg, MI, 365 p.

Dillon, R.T., Jr., 2000, The ecology of freshwater molluscs. Cambridge University Press, Cambridge, UK, 509 p.

II. Paleontology/Geology of the Agate


Breithaupt, B.H., 1983, Goniobasis agate. Rocks and Minerals, 58(5): 247.

Dolenc, A., 1979, Turritella agate – a new find in southwest Wyoming. Lapidary Journal 33(8): 1692.

Dolenc, A., 1981, Turritella agate: update. Lapidary Journal 34(11): 2484-2485.

Eloxite Corporation, 1971, Revised Wyoming collecting localities and latest collecting information. Eloxite Corporation, Wheatland, WY, 35 p. [ref in Hausel and Sutherland, 2000]

Graham, K.L. 1996. Rockhounding Wyoming. Falcon (Globe Pequot Press), Guilford, CT, 158 p.

Grande, L., 1984, Paleontology of the Green River Formation, with a review of the fish fauna. Geological Survey of Wyoming, Bulletin 63, 333 p.

Hanley, J.H., 1974, Systematics, paleoecology, and biostratigraphy of non-marine Mollusca from the Green River and Wasatch Formations (Eocene), southwestern Wyoming and northwestern Colorado. PhD Thesis, University of Wyoming, 285 p.

Hanley, J.H., 1975, Paleosynecology of nonmarine Mollusca from the Green River and Wasatch Formations (Eocene), southwestern Wyoming and northwestern Colorado. Pp. 235-262 In Structure and classification of paleocommunities. R.W. Scott and R.R. West, eds., Dowden, Hutchinson and Ross, Stroudsburg, PA

Hausel, W.D., 2004, Guide to prospecting and rock hunting in Wyoming. Information Pamphlet 11, Wyoming State Geological Survey, 28 pp.

Hausel, W.D., 1986, Minerals and rocks of Wyoming. Wyoming State Geological Survey Bulletin 66, 117 p.

Hausel, W.D., and Sutherland, W.M., 2000, Gemstones and other unique minerals and rocks of Wyoming - a field guide for collectors. Wyoming State Geological Survey Bulletin 71, 268 p.

Hausel, W.D., G.G. Marlatt, E.L. Nielsen, and R.W. Gregory. 1994. Study of metals and precious stones in southern Wyoming. Wyoming State Geological Survey Open File Report 94-2, 61 p.

Jackson, M.W., 1972, Wyoming Fossil Agate: Rock and Gem, v. 2, no. 9, p. 70-73.

Johnson, C., 1973, Western gem hunters atlas. Cy Johnson and Son, Susanville, CA, 79 p.

Lewis, W.S., 1947, Mineralogical thoughts. Hobbies–The Magazine for Collectors 52(10):150.

Sinkankas, J., 1964, Gemstones of North America. Van Nostrand Reinhold, NY, 675 p.

Spendlove, E., 1977, Wyoming Turritella agate. Field trip: it's in the Delaney Rim South of Wamsutter. Rock and Gem 7(6):52-55.

Sutherland, W.M., 1990, Gemstones, lapidary materials, and geologic collectibles in Wyoming. Wyoming State Geological Survey Open File Report 90-9, 53 p.

Zeitner, J.C. 1963, Active localities of the Eastern Slope and Midwest. Lapidary Journal 17(1):124-140.

Zeitner, J.C., 1964, More agate varieties. Lapidary Journal 18(2): 345-351.

III. Geology/Paleontology of the Green River Formation

Bradley, W.H., 1929, Algae reefs and oolites of the Green River Formation. US Geological Survey Professional Paper 154-G

Bradley, W.H., 1964, Geology of the Green River Formation and associated Eocene rocks in southwestern Wyoming and adjacent parts of Colorado and Utah. US Geological Survey Professional Paper 496-A, 86 p.

Buchheim, H.P., 1978, Paleolimnology of the Laney Member of the Eocene Green River Formation. PhD Thesis, University of Wyoming

Grande, L., 1984, Paleontology of the Green River Formation, with a review of the fish fauna. Geological Survey of Wyoming, Bulletin 63, 333 p.

Hanley, J.H., 1974, Systematics, paleoecology, and biostratigraphy of non-marine Mollusca from the Green River and Wasatch Formations (Eocene), southwestern Wyoming and northwestern Colorado. PhD Thesis, University of Wyoming, 285 p.

Hanley, J.H., 1975, Paleosynecology of nonmarine Mollusca from the Green River and Wasatch Formations (Eocene), southwestern Wyoming and northwestern Colorado. Pp. 235-262 In Structure and classification of paleocommunities. R.W. Scott and R.R. West, eds., Dowden, Hutchinson and Ross, Stroudsburg, PA

Surdam, R.C., and K.O. Stanley, 1979, Lacustrine sedimentation during the culminating phase of Eocene Lake Gosiute, Wyoming (Green River Formation). GSA Bulletin 90: 93-160.

IV. Formation of Agate

Götze, J., M. Tichomirowa, H. Fuchs, J. Pilot, and Z.D. Sharp, 2001, Geochemistry of agates: a trace element and stable isotope study. Chemical Geology 175: 523-541.

Heaney, P.J., 1993, A proposed mechanism for the growth of chalcedony. Contributions to Mineralogy and Petrology 115: 66-74.

Heaney, P.J., and A.M. Davis, 1995, Observation and origin of self-organized textures in agates. Science 269: 1562-1565.

Moxon, T., 1996, Agate: microstructure and possible origin. Terra Publications, Auckley, Doncaster.

Pabian, R.K., and A. Zarins, 1994, Banded agates. Origins and inclusions. Nebraska Conservation and Survey Division, Educational Circular no. 12, 32 p.

Quick, L., 1963, The book of agates and other quartz gems. Chilton Books, Philadelphia, 232 p.

Wang, Y., and E. Merino, 1990, Self-organizational origins of agates: banding, fiber twisting, composition, and dynamic crystalization model. Geochimica et Cosmochimica Acta 54: 1627-1638.

V. Crystal Healing

Bourgault, L., 1997, American Indian secrets of crystal healing. Foulsham, London, 128 p.

Eason, C., 2003, The illustrated directory of healing crystals: a comprehensive guide to 150 crystals and gemstones. Vega Books, 160 pp.

Hall, J., 2003, The crystal bible: a definitive guide to crystals. Walking Stick Press, Cincinnati, OH, 400 pp.

Stein, D., 1996, Healing with gemstones and crystals. The Crossing Press, Freedom, CA, 155 p.

VI. Why Crystal Healing is Ridiculous

Gardner, M., 1991, The new age: Notes of a fringe-watcher. Prometheus Books, 273 pp.

Gray, W.D., 1991, Thinking critically about new age ideas. Wadsworth Publishing, Belmont, CA, 164 pp.

Randi, J., and A.C. Clarke, 1997, Encyclopedia of claims, frauds, and hoaxes. St. Martin's Griffin, 336 pp.

Sagan, C., 1996, The demon-haunted world. Science as a candle in the dark. Random House, New York, 457 p.