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Obsidian

Big Photo

Milos Island (Melos), Cyclade Islands (Cyclades; Kikladhes; Nomos Kikladhon), Kykládes Prefecture, Aegean Islands (Aiyaíon) Department, Greece
© Martins da Pedra

Show Obsidian Photos (27)
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: "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.

Classification of Obsidian

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Physical Properties of Obsidian

Lustre:Vitreous
Diaphaneity (Transparency):Translucent
Colour:black, bluish, mahogany, golden, peacock, etc - the colors due largely to refraction by microscopic bubbles.
Fracture:Conchoidal

Other Names for Obsidian

Synonyms:
Apache TearsBergmahoganyBlack Lava GlassŒqinolitVolcanic Glass
XagaŒqinolite
Other Languages:
Spanish:Œqinolita
Varieties:
Mahogany ObsidianRainbow ObsidianSnowflake Obsidian

Other Information

Health Warning:Obsidian is a natural glass and may have razor-sharp edges that can easily cut skin and flesh. Handle with care. Do not grind dry since long-term exposure to finely ground powder may lead to silicosis.

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.

Internet Links for Obsidian

Search Engines:
  • Look for Obsidian on Google
  • Look for Obsidian images on Google
    • Mineral Dealers:
  • Find Obsidian on www.crystalclassics.co.uk
  • SpiriferMinerals.com - high quality specimens
  • Fabre Minerals - search for Obsidian specimens
  • The Arkenstone - Fine Minerals
  • Buy Fine Minerals from mineralsweb.com
  • Fine Minerals from Dan Weinrich Minerals
  • rare and unusual minerals mainly crystallized
  • Search for Obsidian at Thames Valley Minerals
  • Wilensky Fine Minerals
  • Mineral Classics - Worldwide Collector Quality Minerals and Gems
  • Rare and Unusual minerals at Mineralogical Research Company
  • Lapis Mineral Magazin
    • Jobs:
  • Mining & Geology Jobs

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    Localities for Obsidian

    Hide Locality List
    The 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.
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    (TL) indicates type locality. ? 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
    Armenia
     
    http://geo.web.ru/druza/page-47.html
    Bolivia
     
    • Potosí Department
    		Alfredo Petrov collection
    Ethiopia
     
    • Showa Province
    Greece
     
    • South Aegean Department
      • Dodekánisos (Dodekánissa) Prefecture
        • Dodecanese Islands
    		L. Rantos collection
    Lefteris Rantos
    Hungary
     
    • Borsod-Abaúj-Zemplén Co.
      • Zempléni Mts.
    		Koch: Minerals of Hungary,1986
    Iceland
     
    • Myvatn
    		Found by Frank de Wit
    Italy
     
    • Sicily
      • Messina Province
        • Lipari
          • Eolie Islands (Aeolian Islands)
            • Lipari Island
              • Lipari
    		Antonio Borrelli and Tamás Ungvári collections
    • 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 Island
      • Hidaka Province
        • Monbetsu (Mombetsu)
    		Masutomi Museum specimens (Kyoto)
    • Tokyo Prefecture
      • Volcano Islands (Kazan Rettou)
    Mexico
     
    Smith, 1949. Gemstones, 10th ed. revised
    Smith, 1949. Gemstones, 10th ed. revised
    Slovakia
     
    • Košice Region
      • Zemplínske Mts
    		Kaličiak, M., Ďuďa, R., 1996: Geolgický vývoj, stavba a metalogenéza neovulkanitov na Východnom Slovensku. Manuskript, Archív Geofond, Bratislava, 83p
    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
              • Picketpost Mountain area
    		MRDS database Dep. ID #10064153, MRDS ID #TC38413.
    MRDS database Dep. ID #10064155, MRDS ID #TC38415.
        • Superior District
          • Superior
            • Picketpost Mountain area
    		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.
    		CFMS Newsletter, January 2003
      • Inyo Co.
        • Coso Hot Springs
    		[www.johnbetts-fineminerals.com]
      • Lake Co.
    		U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
      • Modoc Co.
    [var: Mahogany Obsidian] P Cristofono collection
        • Mono Lake
      • Napa Co.
    		U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
    • Colorado
      • Hinsdale Co.
        • Galena District (Henson Creek District)
    		Minerals of Colorado (1997) E.B. Eckels
    • Hawaii
      • Hawaii Co.
        • Hualalai Volcano
    		www.hawaiinews.com/archives/volcano_watch/000309.shtml
    • 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
      • Doña Ana Co.
    		Minerals of New Mexico 3rd ed.
    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
      • Lake Co.
    • Utah
      • 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.
    		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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