Log InRegister
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat Articles
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsThe ElementsUsersBooks & MagazinesMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Thunder Egg

This page is currently not sponsored. Click here to sponsor this page.
Hide all sections | Show all sections

About Thunder EggHide

A Thunder Egg is a nodule-like or geode-like geological structure with some adhering silicified host rock comprising the outer zone of the thunder egg. Thunder Eggs are usually composed of quartz, agate, opal, and/or visibly crystalline quartz. A common feature of thunder eggs is that the infilling material might not have concentrically formed layers. Often thunder eggs have both an outer zone that is concentric but the central material is layered as if they were sedimentary layers. The layers may have contrasting colors.

An origin for thunder eggs that has been proposed is that they are the interior of cavities/vesicles/gas bubbles in rhyolitic lava flows. As the silica-filled cavities are harder than the surrounding rock they are often weathered out, or partly weathered out, of their source rock.

See also Geode.

Common AssociatesHide

Associated Minerals Based on Photo Data:
Agate13 photos of Thunder Egg associated with Agate on mindat.org.
Opal7 photos of Thunder Egg associated with Opal on mindat.org.
Chalcedony5 photos of Thunder Egg associated with Chalcedony on mindat.org.
Quartz4 photos of Thunder Egg associated with Quartz on mindat.org.
Precious Opal2 photos of Thunder Egg associated with Precious Opal on mindat.org.
Calcite2 photos of Thunder Egg associated with Calcite on mindat.org.
1 photo of Thunder Egg associated with on mindat.org.
Plume Agate1 photo of Thunder Egg associated with Plume Agate on mindat.org.

Other InformationHide

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

Internet Links for Thunder EggHide

Localities for Thunder EggHide

This 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.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
  • Chubut Province
    • Languiñeo department
      • Piedra Parada
ARAGON, E. et al. Petrogenesis of thundereggs in Eocene rhyolite domes of central Chubut, Patagonia. Rev. Asoc. Geol. Argent. [online]. 2006, vol.61, n.3, pp. 347-354.
  • Queensland
    • Etheridge Shire
Van King
    • Scenic Rim Region
      • Darlington Range
        • Mount Tamborine
Myatt, B. (1972) Australian and New Zealand Gemstones. Paul Hamlyn Pty Ltd., 511 pp.; Ben Grguric collection
  • Victoria
    • Wellington Shire
Birch, W.D. and Henry, D.A. (1999) Gem Minerals of Victoria. Mineralogical Society of Victoria - Special Publication No.4 (120 pages).
  • Chihuahua
    • Mun. de Janos
Rolf Luetcke specimens
  • California
    • Santa Clara Co.
      • San Jose
        • Lone Hill
Cisneros, Eugene (2013), Mineralogical Research Company, private communication to Mindat/org.
  • Idaho
    • Clark Co.
      • Spencer
David L. Crosby
  • New Mexico
    • Hidalgo Co.
      • Pyramid Mts
Flege, R. F., (1959) Geology of Lordsburg Quadrangle, Hidalgo County, New Mexico, NMBMGR Bulletin 62
    • Luna Co.
      • Carrizalillo District
NMBGMR Open-file Report OF-459
      • Little Florida Mountains District
NMBGMR Open-file Report OF-459
NMBGMR Open-file Report OF-459
  • Oregon
    • Baker Co.
      • Durkee
Tschernich, Rudy, 1992, Zeolites of the World
    • Jefferson Co.
      • Madras
Van King
  • Utah
    • Iron Co.
Dave Crosby field collected specimens
Mineral and/or Locality  
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Public Relations by Blytheweigh.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2019, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: April 19, 2019 01:33:08 Page generated: April 15, 2019 17:51:25
Go to top of page