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  Category:Natrodufrénite – Wikimedia Commons

  https://commons.wikimedia.org/wiki/Category:Natrodufr%C3%A9nite?uselang=de

  Keine Beschreibung vorhanden.

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  Mineralogie.co.de - Ihr Mineralogie Shop

  http://www.mineralogie.co.de

  Photo Atlas of Mineral Pseudomorphism, Gesteinsbestimmung im Gelände, Introduction to Clay Minerals, Gems and Gemstones: Timeless Natural Beauty of the Mineral World, Essentials of Igneous and Metamorphic Petrology,

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  The World of Opals - Allan W. Eckert - Google Books

  http://books.google.de/books?id=vGewAkLkmvIC&pg=PA110&lpg=PA110&dq=Mintabie+eckart+opals&source=bl&ots=Lb-xfmx1nn&sig=Hx7Mk7ph0a

  Centuries after it was first discovered, the opal remains the undisputed Queen of Gems. A stone of incredible beauty and variety, with a background rich in myth, adventure, and intrigue, it is considered by many to be the most desirable, the most handsome,…

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  The World of Opals - Allan W. Eckert - Google Books

  http://books.google.de/books?id=vGewAkLkmvIC&pg=PA115&lpg=PA115&dq=galaxy+boulder+opal&source=bl&ots=Lb-xhrt5jl&sig=9E9SY1pTt_S-

  Centuries after it was first discovered, the opal remains the undisputed Queen of Gems. A stone of incredible beauty and variety, with a background rich in myth, adventure, and intrigue, it is considered by many to be the most desirable, the most handsome,…

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  The World of Opals - Allan W. Eckert - Google Books

  https://books.google.de/books?id=vGewAkLkmvIC&pg=PA177#v=onepage

  Centuries after it was first discovered, the opal remains the undisputed Queen of Gems. A stone of incredible beauty and variety, with a background rich in myth, adventure, and intrigue, it is considered by many to be the most desirable, the most handsome,…

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  The World of Opals - Allan W. Eckert - Google Books

  http://books.google.de/books?id=vGewAkLkmvIC&pg=PA120&lpg=PA120&dq=americus+australis+eckert&source=bl&ots=Lb0pelx9ot&sig=tS7hDA

  Centuries after it was first discovered, the opal remains the undisputed Queen of Gems. A stone of incredible beauty and variety, with a background rich in myth, adventure, and intrigue, it is considered by many to be the most desirable, the most handsome,…

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  The World of Opals - Allan W. Eckert - Google Books

  http://books.google.de/books?id=vGewAkLkmvIC&pg=PA68&lpg=PA68&dq=Johannes+Menge+opal&source=bl&ots=Lb-xfly2iq&sig=1RpIr7jRiiJ7po

  Centuries after it was first discovered, the opal remains the undisputed Queen of Gems. A stone of incredible beauty and variety, with a background rich in myth, adventure, and intrigue, it is considered by many to be the most desirable, the most handsome,…

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