Gedanit

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Gedanit from Bitterfeld; Collection: Natural History Museum Mauritianum Altenburg.

Gedanite is a type of amber that was described by Otto Helm in 1878 , he published additional information in 1896. Gedanite was found as an accessory component in Baltic amber (succinite), both in mining and washed up on the Baltic coasts. The name goes back to the Latin word Gedanum for the city of Danzig . From Bitterfeld amber deposits Gedanit is known since 1986th Further finds have been described from northern Ukraine ( Klessiw near Rivne ). The infrared spectrum of amber, which was found on the Siberian Taimyr Peninsula in the Dolgan Formation ( Cenomanium , Upper Cretaceous), shows a remarkable similarity to that of Gedanite.

The color of the mostly clear Gedanite is usually light wine yellow to golden yellow, rarely dirty yellow and opaque. The dusting, snow-white weathering bark is characteristic and very different from succinite. The amber sorters referred to it as "friable" or "immature amber" because of its extreme fragility and rejected it as unsuitable for making jewelry. In contrast to succinite, Gedanite does not contain succinic acid . Gedanite is softer than succinite, the Mohs' hardness is 1.5 to 2.0. He is unlike succinite in organic solvents much more soluble in diethyl ether z. B. 63% and in linseed oil even 100%. The publication from 1896 contains a comparison of the different solubility. Due to the different properties, Otto Helm saw it as certain that the parent plant of Gedanite is not identical to that of Succinite. This assumption has been questioned for a long time, see below. On the basis of infrared spectrographic investigations on finds from Bitterfeld, it appears certain that the parent plant of Gedanit is the extinct coniferous species Cupressospermum saxonicum .

Gas chromatographic and infrared spectroscopic follow-up examinations of pieces called Gedanite from various scientific collections in the 1980s and 1990s have confirmed that two different fossil resins are present, which can be distinguished from one another and from succinite on the basis of their content of succinic acid and their infrared spectrum. The analysis of individual samples by Beck (1986) and Lambert (1988) in one case produced an infrared spectrum which is identical to that of succinite, and in the other case led to a result that was significantly different from this. To distinguish between these two (Gedanite) "variants", the name "Gedano-Succinite" introduced by Sawkiewicz was adopted for the variant with a low content of succinic acid, while Gedanite only refers to the variant without succinic acid. Other authors have even found transitional forms between succinite and gedanite, which fueled doubts as to whether conclusions about their botanical source can be drawn from the chemical structure of fossil resins. The assumption that Gedanite, Gedano-Succinite and Succinite could only be stages of a diagenetic alteration of one and the same resin is also speculative .

Otto Helm had already mentioned the inclusions found in the Gedanit ; according to some annual reports from the West Prussian Provincial Museum in Gdansk, where Helm's collection that had not been preserved was kept until the Second World War. Most of the museums specializing in amber, such as the German Amber Museum in Ribnitz-Damgarten , have Gedanite pieces on display.

Web links

Commons : Gedanite from Bitterfeld  - Collection of images, videos and audio files

Individual evidence

  1. ↑ a b Otto Helm: Gedanit, a new fossil resin . In: Archive for Pharmacy, magazine of the German Pharmacists' Association , Volume 5, Volume 10, Issue 6, Hall 1878, pages 503-507 (online)
  2. ↑ a b Otto Helm: Mittheilungen about amber - XVII: About the Gedanite, Succinite and a variety of the latter, the so-called friable amber . In: Writings of the Natural Research Society in Danzig, NF , Volume 9, Danzig 1896, pages 52-57 (online)
  3. ^ Roland Fuhrmann, Rolf Borsdorf: The amber types of the Lower Miocene of Bitterfeld. In: Journal for Applied Geology , Volume 32, Berlin 1986, Pages 309-316 PDF .
  4. ↑ E. Perkovsky et al .: Rovno Amber. In: Biodiversity of fossils in amber from the major world deposits. Ed .: D. Penney; Pages 116-136; ISBN 978-0-9558636-4-6
  5. ↑ VV Zherikhin et al .: An overview of Asian fossil resins with inclusions. In: Amber - views - opinions. Warsaw 2006.
  6. ^ Roland Fuhrmann: The bitter fields amber. In: Mauritiana , Volume 21, Altenburg 2010, ISSN  0233-173X , pages 13-58, PDF
  7. ↑ Dieter Hans Mai, Wilfried Schneider: About an ancient conifer in the Young Tertiary and its importance for lignite and amber formation. In: Feddes Repetitorium. Volume 99, Berlin 1988, pages 101-112.
  8. ↑ Beck 1986 and Lambert 1988, quoted in George O. Poinar, Jr .: Life in Amber . 350 pages, 147 figs., 10 plates, Stanford University Press, Stanford (Cal.) 1992, ISBN 0-8047-2001-0 .
  9. ↑ Swiatoslaw S. Sawkiewicz: Jantar , Leningrad 1970, 192 pages,
  10. ^ A b Stout, Beck, Kosmowska-Ceranowicz: Gedanite and Gedano-Succinite. In: Amber, Resinite, and Fossil Resins. ACS Symposium Series 617, Washington, DC, 1995.
  11. ↑ J. Koller and B. & U. Baumer: The investigation of amber, amber oils and amber varnishes. In: Metalla special issue, Bochum 1997.
  12. ↑ B. Kosmowska-Ceranowicz: The history and present possibilities of Establishing of amber collection in Gdańsk. In: Amber - views - opinions. Pages 184–188, Danzig / Warsaw 2006 (first publication of the article 1998).

literature

  • Günter Krumbiegel, Brigitte Krumbiegel: Amber - Fossil Resins from all over the world . 3. Edition. edition Goldschneck, Quelle & Meyer, Wiebelsheim 2005.
  • CW Beck et al .: Beckerite . In Phys. Chem. Minerals 13: 411-413; 1986.
  • JB Lambert et al .: Analysis of European amber at Carbon-13 Nuclear Magnetic Resonanc Spectroscopy . In Archaeological Chemistry 4: 381-388; 1988.