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Obsidian

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Colour:
black, bluish, mahogany, ...
Volcanic glass - a rock rather than a mineral, it is a mixture of cryptocrystalline grains of silica minerals in a glass-like suspension, a super-cooled liquid. Obsidian is formed in the latest stage of volcanic eruptions, the silicas left over after most of the other elements and water have been used up are ejected or flow out and rapidly chilled at surface temperatures.

Note on "Transparent/Translucent Obsidian":
A lot of gem-quality water-clear variously coloured 'obsidian' has been offered for sale on the internet (in particular on auction websites) with a variety of sources listed. The material offered for sale is in fact an artificial glass mass-produced in places such as Indonesia.

Visit gemdat.org for gemological information about Obsidian.

Classification of Obsidian

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Please feel free to link to this page.

Physical Properties of Obsidian

Vitreous
Diaphaneity (Transparency):
Translucent
Colour:
black, bluish, mahogany, golden, peacock, etc. - the colors due largely to refraction by microscopic bubbles (and microscopic mineral inclusions such as magnetit in "Rainbow Obsidian").
Fracture:
Conchoidal

Other Names for Obsidian

Name in Other Languages:
Simplified Chinese:火山玻璃
Spanish:Œqinolita

Other Information

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Obsidian

Reference List:
Stevenson, R.J., Dingwell, D.B., Webb,S.L., and Bagdassarov, N.S. (1995) The equivalence of enthalpy and shear stress relaxation in rhyolitic obsidians and quantification of the liquid-glass transition in volcanic processes. Journal Volcan. Geotherm. Res.: 68: 297-306.

F. Eder, C. Neelmeijer, N. Pearce, M. Bichler, J.H. Sterba, T. Ntaflos, S. Merchel (2013): Volcanic glass under fire - a comparison of three complementary analytical methods. X-Ray Spectrometry, 42, 412-422.

http://members.peak.org/~obsidian/index.html (International Association for Obsidian Studies)

Internet Links for Obsidian

Localities for Obsidian

map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
(TL) indicates type locality for a valid mineral species. (FRL) indicates first recorded locality for everything else. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
Antarctica
 
  • Eastern Antarctica
    • Victoria Land
      • Malta Plateau
Ganovex III expedition
Argentina
 
  • Catamarca
    • Antofagasta de la Sierra Department
R. N. Alonso (1999). Los salares de la Puna y sus recursos evaporíticos, Jujuy, Salta y Catamarca. En: Recursos Minerales de la República Argentina (Ed. E.O. Zappettini), Instituto de Geología y Recursos Minerales. SEGEMAR, Anales 35: 1907-1921.
Raúl Jorge Tauber Larry
  • Salta
Raúl Jorge Tauber Larry
Raúl Jorge Tauber Larry;
    • Los Andes Department
Alonso, R. N., de los Hoyos, L., González Barry, C. E. (2004). Minería, propuestas y reflexiones sobre una actividad productiva esencial. Cámara Minera de Jujuy, Centro de Geólogos de Jujuy.
Alonso, R. N., de los Hoyos, L., González Barry, C. E. (2004). Minería, propuestas y reflexiones sobre una actividad productiva esencial. Cámara Minera de Jujuy, Centro de Geólogos de Jujuy.
Secretaria de Minería, Industria y Recursos Energéticos de la provincia
http://www.unsa.edu.ar/ibigeo/images/PDFs/N3/Obsidiana.pdf
http://www.unsa.edu.ar/ibigeo/images/PDFs/N3/Obsidiana.pdf
http://www.unsa.edu.ar/ibigeo/images/PDFs/N3/Obsidiana.pdf
http://www.unsa.edu.ar/ibigeo/images/PDFs/N3/Obsidiana.pdf
http://www.unsa.edu.ar/ibigeo/images/PDFs/N3/Obsidiana.pdf
http://www.unsa.edu.ar/ibigeo/images/PDFs/N3/Obsidiana.pdf
Alonso, R. N., de los Hoyos, L., González Barry, C. E. (2004). Minería, propuestas y reflexiones sobre una actividad productiva esencial. Cámara Minera de Jujuy, Centro de Geólogos de Jujuy.
Armenia
 
  • Kotayk' Province
http://geo.web.ru/druza/page-47.html
Australia
 
  • Victoria
    • City of Greater Geelong
      • Anakie
        • Mount Anakie
Birch et al. (2008) Australian Journal of Mineralogy, 14(1), 37-42.
Bolivia
 
  • Potosí Department
Alfredo Petrov collection
Canada
 
  • British Columbia
    • Kamloops Mining Division
Richard Gunter Collection
China
 
  • Jiangsu Province
    • Huai'an Prefecture
      • Xuyi Co.
Tianhu Chen, Xiaochun Xu, Shucang Yue, and Jinzhong Li (2002): Geology and Prospecting 38(2), 49-54
Ethiopia
 
  • Oromia Province (Oromiya Province)
Alfredo Petrov field observations, 1972.
  • Sidamo-Borana Province
    • Awassa
Macdonald, R., and Gibson, I.L. (1969): Contributions to Mineralogy and Petrology 24, 239-244.
France
 
  • Auvergne
    • Cantal
      • Cantal Mts
        • Saint-Jacques-des-Blats
Robin Fialip 2014
Georgia
 
  • Samtskhe-Javakheti Region
Alexander G. Tvalchrelidze, Georges Morizot (2003) Mineral Resource Base of the Southern Caucasus and Systems for its Management in the XXIst Century. Springer 204pp
Greece
 
  • Aegean Islands Department (Aiyaíon)
    • Kykládes Prefecture
      • Cyclade Islands (Cyclades; Kikladhes; Nomos Kikladhon)
Martins da Pedra collection
  • South Aegean Department
    • Dodekánisos Prefecture (Dodekánissa)
      • Dodecanese Islands
L. Rantos collection
Lefteris Rantos
Hungary
 
  • Borsod-Abaúj-Zemplén Co.
    • Zemplén Mts (Tokaj Mts)
Koch: Minerals of Hungary,1986
Iceland
 
  • Northeastern Region
    • Myvatn
Found by Frank de Wit
Italy
 
  • Latium
    • Latina Province
Tykot R. H., Setzer T., Glascock M. D., Speakman R. J. (2005): Identification and characterization of the obsidian sources on the island of Palmarola, Italy. Geoarchaeological and Bioarchaeological Studies, 3, 107-111.
  • Sicily
    • Messina Province
      • Eolie Islands (Aeolian Islands)
        • Lipari
          • Lipari Island
Antonio Borrelli and Tamás Ungvári collections
    • Trapani Province
Foerstner E. [H.] (1881): Nota preliminare sulla geologia dell'isola di Pantelleria secondo gli studi fatti negli anni 1874 e 1881. Boll. R. Comit. Geol. Ital., 12, 523-556. Foerstner H. (1984): Ueber künstliche physikalische Veränderungen der Feldspäthe von Pantelleria. Zeits. Kryst. Min., 9, 1, 333-352.
  • Trentino-Alto Adige (Trentino-Südtirol)
    • Trento Province
      • Lagarina Valley
        • Mt. Baldo
          • Ala
            • Pilcante
"Giorgio Bortolozzi (visual identification)"
  • Tuscany
    • Siena Province
      • Murlo
C. Betti, G. Pagani (2000): Minerali del Senese. Cento località mineralogiche nella provincia di Siena. - Protagon Ed. Toscani, Siena
Japan
 
  • Hokkaido
    • Hidaka Province
      • Monbetsu (Mombetsu)
Masutomi Museum specimens (Kyoto)
  • Tokyo Metropolis
    • Volcano Islands (Kazan Rettou)
Wakimizu, T. (1908). The ephemeral volcanic island in the Iwojima group.
Gordon A. MacDonald (1948) Petrography of Iwo Jima. Bulletin of the GSA, 59, 1009-1018.
Gordon A. MacDonald (1948) Petrography of Iwo Jima. Bulletin of the GSA, 59, 1009-1018.
Madagascar
 
  • Antsiranana Province
    • Diana Region (Northern Region)
      • Ambanja District
        • Ampasindava Peninsula
          • Betaimboay
            • Unnamed caldera
Wolfgang Hampel, site visit May 2012
Mexico
 
Smith, 1949. Gemstones, 10th ed. revised
  • Jalisco
    • Mun. de Magdalena
      • San Andreas
Information verbal from Alfredo Banos owner of the mine
Smith, 1949. Gemstones, 10th ed. revised
New Zealand
 
  • North Island
    • Waikato
      • Taupo
Rod Martin personal collection
Giorgio Bortolozzi
Peru
 
J.Hyrsl (2012) Gemstones of Peru, p. 55
J.Hyrsl (2012) Gemstones of Peru, p. 55
  • Junín Department
    • Yauli Province
Hewett, D. F. (1910) Vanadium Deposits in Peru. Transactions of the American Institute of Mining, Metallurgical Engineering 40:274-299
Poland
 
  • Lower Silesia (Dolnośląskie)
    • Kłodzko District
      • Lądek Zdrój commune
Personally collected by Zając Piotr in 2012
Portugal
 
  • Azores District
    • Terceira Island
      • Angra do Heroísmo
Martins da Pedra collection
Museu Natural de História Natural de Lisboa mineral collection, Oct 2014
Slovakia
 
  • Košice Region
    • Trebišov Co.
Matúš Škutka
Kaličiak, M., Ďuďa, R., 1996: Geolgický vývoj, stavba a metalogenéza neovulkanitov na Východnom Slovensku. Manuskript, Archív Geofond, Bratislava, 83p
Turkey
Rui Nunes collection
  • Eastern Anatolia Region
    • Bitlis Province
Rui Nunes collection
USA
 
  • Arizona
    • Coconino Co.
      • Coconino National Forest
Phillips, K.A. (1987), Arizona Industrial Minerals, AZ Dept. of Mines & Mineral Resources Rpt. 4.
Mitchell, 2001. Gem Trails of Arizona, p.56.
      • San Franciscan volcanic field (San Francisco Peaks; San Francisco Mts)
        • O'Leary Peak
Robinson, Henry H. (1913), The San Franciscan volcanic field, AZ, USGS PP 76: 65.
        • Sitgreaves Peak (Sitgreaves Mt.)
Robinson, Henry H. (1913), The San Franciscan volcanic field, AZ, USGS PP 76: 67.
Robinson, Henry H. (1913), The San Franciscan volcanic field, AZ, USGS PP 76: 67.
Robinson, Henry H. (1913), The San Franciscan volcanic field, AZ, USGS PP 76: 67.
    • Graham Co.
      • Black Hills
MRDS database Dep. ID #10024056.
    • Greenlee Co.
      • Shannon Mts
        • Copper Mountain District (Clifton-Morenci District)
          • Clifton
Bearce, 2006. Minerals, Fossils and Fluorescents of Arizona
    • Pinal Co.
      • Pinal Mts
        • Pioneer District
P Cristofono collection
MRDS database Dep. ID #10064155, MRDS ID #TC38415.
      • Superior District
        • Superior
          • Picketpost Mountain area
MRDS database Dep. ID #10064153, MRDS ID #TC38413.
MRDS database Dep. ID #10060368.
    • Yuma Co.
      • Tank Mts
        • Tank Mountains District
Shackley, M.S. (1991) Tank Mountains obsidian - A newly discovered archaeological obsidian source in east-central Yuma County, Arizona: Kiva: 57(1): 17-25.
  • California
    • Imperial Co.
      • Niland
Rogers, Austin Flint (1935), Salton volcanic domes of Imperial County, California (abstract): Geological Society of America, Proceedings, 1934: 328; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 181; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 457; CFMS Newsletter, January 2003.
      • Plaster City
      • Salton Sea
Rogers, Austin Flint (1925), Geology of Cormorant Island, Salton Sea, Imperial County, California, …(abstract): Geological Society of America Bulletin: 37: 219; Rogers, Austin Flint (1928), Natural history of the silica minerals: American Mineralogist: 13: 219; Rogers, Austin Flint (1935), Salton volcanic domes of Imperial County, California (abstract): Geological Society of America, Proceedings, 1934: 328; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 162, 372; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 351.
    • Inyo Co.
      • Coso Mts (Coso Range)
        • Coso District (New Coso District)
          • Sugarloaf Mountain
Rogers, Austin Flint (1922), A new occurrence of cristobalite in California: Journal of Geology: 30: 211-216; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 162.
Rutley, Frank (1890), On composite spherulites in obsidian from Hot Springs, near Little Lake, California: Geological Society of London Quarterly Journal: 46: 423-428; Rogers, Austin Flint (1922), A new occurrence of cristobalite in California: Journal of Geology: 30: 213-215; Bowen, N.L. (1935), Ferrosilite as a natural mineral: American Journal of Science, 5th. Series: 30: 481; Bradley, W.W. (1940), Thirty-sixth report of the State Mineralogist: California Division Mines Report 36: 107; Pemberton, H. Earl (1983), Minerals of California: 351, 386, 457.
Bowen, N.L. (1935), Ferrosilite as a natural mineral: American Journal of Science, 5th. Series: 30: 481 (491 ?); Bradley, W.W. (1940), Thirty-sixth report of the State Mineralogist: California Division Mines Report 36: 107; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 307.
    • Lake Co.
      • Sulphur Creek District (Sulfur Creek District; Wilbur Springs District)
        • Clear Lake Oaks
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
    • Modoc Co.
      • Warner Mts
        • Davis Creek
www.vgms.org/bt/vgms0004.htm (The Ventura Gem & Mineral Society, Inc. (VGMS)).
Industrial West Foundation, Non-Metallics II-D: 71; USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10115839.
        • Sugar Hill
Gems & Minerals (1966): April: 23.
[var: Mahogany Obsidian] P Cristofono collection
Bailey, R. A. (1989) Geologic map of the Long Valley caldera, Mono-Inyo Craters volcanic chain, and vicinity, eastern California. USGS IMAP 1933
Haas, P. (1992), site visit.
USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10031513.
Loney, R.A. (1968) Flow structure and composition of the Southern Coulee, Mono Craters, California – a pumaceous rhyolite flow. Geological Society of America Memorandum 116: 423, 428; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 354, 361.
    • Napa Co.
      • Mayacmas Mts (Mayacamas Mts)
        • Calistoga District (Silverado District)
          • St. Helena
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
    • Siskiyou Co.
      • Cascade Range
        • Cougar Butte
Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 163; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 354.
Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 181; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 459.
  • Colorado
    • Chaffee Co.
      • Nathrop
USGS Bull 1716C
    • Hinsdale Co.
      • Galena District (Henson Creek District)
Minerals of Colorado (1997) E.B. Eckels
  • Hawaii
    • Hawaii Co. (Hawaii Island)
      • Hualalai Volcano
www.hawaiinews.com/archives/volcano_watch/000309.shtml
(Specimens in innumerable collections, often as the wind-spun filiform variety known as "Pele's hair".)
  • Idaho
    • Blaine Co.
      • Snake River Area
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
  • Nevada
    • Esmeralda Co.
NBMG Spec Pub 31 Minerals of Nevada
NBMG Spec Pub 31 Minerals of Nevada
      • Montezuma District
NBMG Spec Pub 31 Minerals of Nevada
    • Lander Co.
      • Wild Horse District
NBMG Bull 80 Geology and Mineral Deposits of Lander County, Nevada
    • Nye Co.
NBMG Spec Pub 31 Minerals of Nevada
    • Washoe Co.
NBMG Spec Pub 31 Minerals of Nevada
  • New Mexico
www.swxrflab.net/mulecr.htm
    • Cibola Co.
James M. Barker, Virginia T. McLemore, Marc L. Wilson, and George S. Austin, (1989) East Grants ridge--A mineral potpourri. in 40th Field Conference New Mexico Geological Society, pp. 325-329.
    • Doña Ana Co.
Minerals of New Mexico 3rd ed.
NMBMMR Bull 11 The Geology of the Organ Mountains
www.swxrflab.net/mulecr.htm
    • Luna Co.
      • Little Florida Mountains District
http://geoinfo.nmt.edu/tour/stateparks/rockhound/home.htm
    • San Juan Co.
Minerals of New Mexico 3rd ed.
    • Sandoval Co.
[var: Mahogany Obsidian] www.cst.cmich.edu/users/dietr1rv/obsidian.htm
      • Valle Grande
Minerals of New Mexico 3rd ed.
  • Oregon
    • Deschutes Co.
      • East Lake
The ORE BIN Volume 31, No.4 April 1969 pp 73-87; Mineralogy of 10 Geothermal boreholes drilled in and around the Newberry Caldera U.S. Geological Survey Professional Paper, Issue 1578 By Keith E. Bargar, Terry E. C. Keith 1999
    • Lake Co.
The Canadian Mineralogist Vol. 45, pp. 551-557 (2007)
  • Utah
    • Beaver Co.
      • Milford
Rick Dalrymple
    • Box Elder Co.
      • Promontory Mts
        • Promontory District
UGMS Bull 117 Minerals and Mineral Localities of Utah
    • Iron Co.
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
    • Juab Co.
      • Dugway Pass area
Rick Dalrymple Collection
UGMS Bull 117 Minerals and Mineral Localities of Utah
    • Millard Co.
      • Antelope Springs (Wheeler Amphitheater)
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
      • Black Rock Desert
UGMS Bull 117 Minerals and Mineral Localities of Utah
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
UGMS Bull 117 Minerals and Mineral Localities of Utah
    • Piute Co.
UGMS Bull 117 Minerals and Mineral Localities of Utah
  • Wyoming
    • Park Co.
      • Yellowstone National Park
www.obsidianlab.com/universe.html
Mineral and/or Locality  
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