Copal (tree resin)

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Madagascar Copal

Copal or Kopal is a collective name for tree resins of various botanical origins that are used as incense and for high-quality paints and varnishes . They are about transparent, yellowish to reddish and glassy hard.

term

The word comes from the Nahuatl word copalli , which means something like "resin". In the Aztec language, the name also stands for incense . The Mayans called Copal “Pom”, which means “brain of heaven”.

In ancient times and in part still today in English-speaking countries, copals were also known as Animé .

Differentiation between copal and resin and amber

The copals can be divided into two broad groups; 1. the hard, real or fossil copals (tropical amber ) and 2. the soft, fake, recent or recent fossil copals.

False copal is a semi-fossil, natural resin that, in contrast to fresh resins, has a much greater hardness and thus a higher melting point .

In contrast to amber, the age of which is measured in millions of years, fake copal - at least in the most common definition of this term - is hardened, sub-fossil resin that is usually between a few decades and a few millennia old. If acetone or a similar solvent is dripped onto Copal, a greasy, sticky surface is formed, while real fossil copal, amber, is not dissolved. The melting point of amber (200 to 380 ° C) is also significantly higher than that of the fake copal (below 150 ° C).

In the 1990s, an attempt was made to classify resins, copal and amber using scientific methods based on their chemical properties. In addition to the ingredients, the degree of polymerization of the resin samples examined plays a role. The results of these analyzes indicate that "[...] it is essentially useless to attempt to determine the age of organic material in sediments solely through chemical analyzes [...]", because the extent of chemical transformation processes due to various influences is determined and resins of the same age can therefore have different stages of development, which lead to different results of the chemical analyzes. However, the results also indicate that Copal is much closer to the recent resin than to amber and even doubts seem appropriate as to whether Copal should be called a subfossil resin.

The question of the age range of Copal is still answered differently in science. It is only clear that the polymerization is not complete with Copal, but with Bernstein it is. The transitions between recent resin and copal and between copal and amber are fluid. For the layman who neither has the equipment to carry out complex chemical analyzes of resin samples nor the specialist knowledge to interpret the results of such investigations, only the tests mentioned above remain. Trade names are often unreliable and misleading.

In scientific literature u. a. for the aforementioned reasons, the term "resin" or "fossil resin" is generally used. Terms such as "amber" or "copal" are considered to be colloquial or commercial terms that are unspecified in a scientific sense.

Live resin coating by "tapping" the trunk of Agathis dammara (Kauri spruce) on the Indonesian island of Java . The product “ Kauri resin ” obtained in this way is also misleadingly referred to as Kauri copal.
Copal from Colombia with numerous organic inclusions (insects, spiders, wings, etc.)

Botanical origin

It is obtained both from deciduous trees ( Hymenaea ) and from conifers such as New Zealand kauri spruce , an araucaria plant . But there are also copals on the market whose botanical origin cannot be easily classified, for example if the subfossil resin from the roots of the trees producing the resin has entered the soil, from which it is only extracted when the trees have long since disappeared . Copal can also be found in secondary deposits due to flooding, such as amber.

Copal and other items on a market stall on "Day of the Dead" in Santiago Tianguistenco, Mexico. In the background, copal is used as an incense.
Copal collectors on Sulawesi Island (formerly Celebes), Indonesia; first half of the 20th century.

Organic inclusions

Similar to amber, copals sometimes contain organic inclusions, such as B. insects or parts of plants. These inclusions in Copal are created in the same way as amber inclusions . In contrast to these, the inclusions in Copal are mostly much better preserved due to their young age. In principle, in contrast to amber inclusions, there is a realistic chance of isolating DNA from preserved tissue of copal inclusions . Because the few inclusions that have been scientifically investigated in more detail from Copal also include extinct species, despite their young age, quite a few paleoentomologists see this aspect as a weighty reason to advance research on Copal inclusions. In particular, copal from Madagascar and Colombia is the focus of research. Another aspect raised in exploring the inclusions in Copal is the fact that Copal is sometimes extracted in huge chunks that can contain an abundance of inclusions. The wealth of forms of hundreds of inclusions in a single piece, organisms that were trapped in the same minute and shared the same habitat with one another, allows conclusions to be drawn about the communities at the time the resin was formed and opens up the opportunity to reconstruct habitats that have since disappeared.

use

In the period between 1853 and 1970, more than 100,000 tons of subfossil Kauri resin (Kauri copal) were produced in New Zealand . Most of this was exported to England and the USA, where the raw material was used in the production of paints and varnishes , but also in handicrafts. The peak of exports with 10,000 tons was reached in 1905. The New Zealand copal deposits were already used intensively by the Maori , who reached the archipelago around 800 years before the first Europeans. Copal was used as fuel and the smoke was used against various insects. Mixed with the juice of a plant similar to our saudi thistle , copal was chewed to care for the teeth; Grinded to powder and mixed with an oil, Copal served as an antiseptic for wound treatment. Burned copal played a role in the creation of the colors for Maori tattoos .

Large quantities of copal were mined in the coastal areas in southern Africa for the purpose of paint production , particularly in the 1920s . In the area of ​​what is now the Democratic Republic of the Congo (at the time the Belgian Congo) there were more than 20,000 tons in 1926 and thus around 97% of the total African copal production. The material occasionally sold as "Kenya amber" or "Tanzania amber" is also copal.

In Mexico , Copal has the same status as we do with incense. The indigenous high cultures of Mesoamerica used Copal as incense in their sacrificial rituals and as a remedy for many types of illnesses (e.g. asthma , colds or diarrhea). In addition, the Maya used Copal for the production of the pigment Maya blue from indigo and palygorskite . The previously very broad use in paint and varnish production has now been reduced to very high-quality instrument and boat varnishes . In the food industry, copal resin is still used today as a paint carrier and sealing substance for the industrial production of Easter eggs .

Subfossil copals were and are still in isolated use today as a basis for high-quality paints.

Then as now, the value of the copal depends on its hardness: the harder (and therefore the higher the melting point), the higher the quality.

Despite its optical properties, which are similar to amber, copal only plays a subordinate role as a raw material for the manufacture of jewelry because of its comparatively low hardness. At the beginning of the 20th century, copals from the Congo were processed into high-quality jewelry boxes by the Belgian company Ebena from Wijnegem , which were decorated with carvings and gold leaf plating.

Copal is sometimes used as a base material for embedding organisms (mostly vertebrates , often lizards). These reconstructions , which are sometimes difficult to recognize , often find their way onto the market as counterfeits of high-quality amber inclusions.

Varieties

Over time, a vast number of terms have developed for Copale that neither follow a uniform system nor are used uniformly in the literature. Formations of terms that follow the rules of mineralogical nomenclature (e.g. agathocopalite or legumocopalite for copals that are made from the resin of agathis or legumes ) have not caught on. Some of the names widely used today for varieties of Copal are

Further copal occurrences with organic inclusions are known from: Allendale, Victoria (Australia) ; Mizunami , Japan. With an age of 33,000 years, the latter is considered to be the oldest copal deposit.

The Colombian resin is often offered in the trade as amber. Its age is hotly debated, although the C14 dating of a sample of this material has shown an age of less than 250 years, which means that it cannot be classified as amber.

Copalin and Copalit

A fossil resin with the name Copalin ( English copaline ) or Copalit (English copalite ), reminiscent of Copal, is known from the London Clay Formation ( Ypresium , Lower Eocene ) on Highgate Hill in north London . Due to the age of the formation (around 50 million years) and due to the fact that (fossil) resins cannot be younger than the matrix in which they are found, however, it is a "mature" fossil resin ( Amber), the botanical source of which is assumed to be a tree from the balsam family ( Burseraceae ). Under the same name ("Copalin"), an approximately 50 million year old fossil resin (also amber, not Copal) from the Greifenstein sandstone in Austria is mentioned in the literature . The names reminiscent of Copal go back to the fact that the composition of a fossil resin found in Austria was compared towards the end of the 19th century with that of the Eocene resin from London and both showed a certain similarity to Copal. Other authors later transferred this name to fossil resins from other Austrian sites, so that in the literature a wide variety of fossil resins, none of which have anything to do with Copal, are mentioned under this name.

See also

Web links

Commons : Copal (tree sap)  - collection of images, videos and audio files

literature

  • Hermann Kühn: Preservation and care of works of art - material and technology, conservation and restoration , Klinkhardt & Biermann, Munich, 2001, ISBN 978-3-7814-0428-1 .
  • Jürgen Hevers: Extraction and processing of resin and copal . In: Amber - Tears of the Gods. P. 65–82, various illustrations, publications from the German Mining Museum No. 64, Bochum 1996, ISBN 3-921533-57-0 .
  • George O. Poinar, Jr .: Life in Amber. 350 pp., 147 figs., 10 plates, Stanford University Press, Stanford (Cal.) 1992, ISBN 0-8047-2001-0 .
  • AH & AW Reed: The Gumdiggers. 193 pp., Wellington (New Zealand) 1972, ISBN 978-0-589-00732-4 .
  • D. Penney & RF Preziosi: On Inclusions in Subfossil Resins (Copal). In: Biodiversity of fossils in amber from the major world deposits. Ed .: D. Penney, Manchester (UK) 2010. ISBN 978-0-9558636-4-6 .

Individual evidence

  1. ↑ K. Dieterich, E. Stock: Analysis of the resins. Second edition, Springer, 1930, ISBN 978-3-642-89462-6 , pp. 231-293.
  2. ↑ Ronald L. Bonewitz: Stones & Minerals: Rocks, minerals, precious stones, fossils . Dorling Kindersley, Munich 2009, ISBN 978-3-8310-1469-9 .
  3. ↑ Jean.H Langenheim: "Biology of Amber-Producing Trees: Focus on case studies of" Hymenaea "and" Agathis ". In Amber, Resinite, and Fossil Resins. ACS Symposium Series 617 , Washington, DC, 1995, ISBN 0-8412 -3336-5 .
  4. ^ Hanns Guenther Seyb: Botany and drug science. Part I and II, Springer, 1956, ISBN 978-3-663-04058-3 (reprint), p. 160 f.
  5. ↑ a b c K. B. Anderson and J. C. Crelling (Eds.): Amber, Resinite, and Fossil Resins. ACS Symposium, Series 617 , Washington 1995, ISBN 0-8412-3336-5 , (translation of the quote by the editor).
  6. ^ Penney & Preziosi: On Inclusions in Subfossil Resins (Copal). In: David Penney (Ed.): Biodiversity of fossils in amber from the major world deposits. Manchester 2010, ISBN 978-0-9558636-4-6 .
  7. ↑ B. Kosmowska-Ceranowicz: Amber forgeries - copals and artificial resins. (Contribution from 2001), In: Amber –views - opinions. International Amber Association, Warsaw / Gdańsk 2006, ISBN 83-912894-1-9 .
  8. ↑ George and Roberta Poinar: The Quest for Life in Amber. Cambridge (Massachusetts) 1994, ISBN 978-0-201-48928-6 .
  9. ↑ C. L. Mantell et al. a .: The Technology of Natural Resins. New York 1942, quoted in: Jean H. Langenheim: Plant Resins. Portland 2003, ISBN 978-0-88192-574-6 .
  10. ↑ Dieter Schlee: The Bernstein Cabinet. In: Stuttgart contributions to natural history. Series C, issue 28, Stuttgart 1990.
  11. ↑ Julius Wiesner : The raw materials of the plant kingdom. 5th ed., Constantin von Regel (Ed.), J. Cramer, Weinheim 1962.
  12. ^ Silvia Glaser: Kopal. In: Historical plastics in the Germanic National Museum. Verlag des Germanisches Nationalmuseums, Nuremberg 2008, ISBN 978-3-936688-37-5 , pp. 8-10.
  13. ↑ N. Vavra: Copals, amber, fossil resins: problems of their nomenclature and systematics. Digression. f. and publ. DGG, Hannover 2013, ISBN 978-3-86944-094-1 , pp. 68-75.
  14. ↑ a b Ryan J. Case et al. a .: Chemistry and Ethnobotany of Commercial Incense Copals, Copal Blanco, Copal Oro, and Copal Negro, of North America. In: Economic Botany. 57 (2) , pp. 189-202, New York 2003, JSTOR 4256678 , doi : 10.1663 / 0013-0001 (2003) 057 [0189: CAEOCI] 2.0.CO; 2 .
  15. ↑ P. H. List, L. Hörhammer: Hagers Handbook of Pharmaceutical Practice . 4th volume Cl-G , 4th edition, Springer, 1973, ISBN 978-3-642-80621-6 , p. 286 ff.
  16. ↑ Felix Bachmair: Antimicrobial effect of selected resins on airborne germs. Diploma thesis, University of Vienna, 2013, pp. 33–40, online (PDF; 2.93 MB), at othes.univie.ac.at, accessed on January 3, 2017.
  17. ^ A b P. C. Rice: Amber the golden gem of the ages. 3rd edition, Kosciuszko Foundation, New York 1993, ISBN 0-917004-22-1 .
  18. ↑ R. Hegnauer : Chemotaxonomy of Plants: Volume XIb-1: Leguminosae Part 2 , Birkhäuser, 1996, ISBN 3-7643-5165-9 , p. 158.
  19. ^ John H. Wiersema, Blanca León: World Economic Plants: A Standard Reference. Second Edition, CRC Press, 2013, ISBN 978-1-4398-2142-8 , p. 849.
  20. ↑ David A. Grimaldi: Amber - Window to the Past. New York 1996, ISBN 0-8109-1966-4 .
  21. ^ Encyclopædia Britannica . Eleventh Edition (1910-1911).
  22. ↑ Christoph Lühr: Characterization and classification of fossil resins - dissertation from 2004 (University of Duisburg-Essen, Campus Duisburg), (PDF; 6.81 MB), on duepublico.uni-duisburg-essen.de, accessed on 9. October 2016.
  23. ^ G. Starkl: About new mineral occurrences in Austria. In: Yearbook of the k. k. Geol. Reichsanstalt. 33 , Vienna 1883, pp. 635-658.
  24. ^ N. Vavra: Chemical Characterization of Fossil Resins ("Amber") - A Critical Review of Methodes, Problems and Possibilities: Determination of Mineral Species, Botranical Sources and Geographical Attribution. In treatises of the Federal Geological Institute. Volume 49, pp. 147–157, Vienna, 1993, ISBN 978-3-900312-85-5 , PDF (1.1 MB) on ZOBODAT