Talk:Copal

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This needs serious attention since this article is er, just wrong. Copal is derived from the Spanish word copalli and is a generic term referring to the resinous secretions of a wide range of trees, both in terms of species and in geographic distribution. I will remove the obviously erroneous stuff and try and make sense of this asap. Sjc 13:00, 7 Jul 2004 (UTC)

I’ve removed additions that seem way out of bounds for WP. Copal is a colloquial term. The references cited are non-scientific, and in one case commercial. The content that seems copied is apparently non-verifiable from an authoritative source, and suffers from begging the question issues. SNP 02:45, 8 February 2007 (UTC)

Genus?

I have removed "often from members of the genus Bursera" from the lead paragraph. Previously it said "often from members of the genus Copaifera." Neither assertion was sourced. In The Artist's Handbook of Materials and Techniques, Ralph Mayer says, "a dozen distinct species of varnish resins from many parts of the world, having widely varied properties, are all legitimately listed as copals." (p. 231, fifth edition)

Better to say nothing, than to be in error. __ Just plain Bill (talk) 23:38, 29 November 2010 (UTC)

Duplicated quote

The "There is a great confusion..." Walter Hough quote appears twice in the notes... AnonMoos (talk) 01:58, 19 February 2011 (UTC)

Colloquial terminology

This article makes statements that can't be scientifically verified, and uses contains colloquial terminology that appears to originate with participants in a cottage industry associated with amber. The term subfossil seems to be used to associate fossilization with degree of polymerization for which no scientific scale exists. The claim that tree resin from Colombia and Madagascar is usually not older than about 200 years appears to come from a popular book. One sample and one measurement from one locality can't be generalized to such a large geographic area where trees have been producing resin for millions of years. Similarly, trees in tropical zones of the Western Hemisphere have been producing resin for millions of years, and ages of tree resin buried in the ground should vary correspondingly. SNP 13 April, 2011

What sources where you looking at that said Copal was not subfossil? --Kevmin § 19:45, 13 April 2011 (UTC)

I spent time researching this for a few years (see my 2007 comment above). I found it interesting since I was trained as a polymer chemist. There really are no authoritative sources in the literature, given that science has little interest in copal and amber – even the entomology involved adds little to our understanding of evolution. The best source I found was an Geochemistry Division of the American Chemical Society symposium report from 1995 (ISBN13: 9780841233362), and particularly the comments of Dr. Anderson of Argonne National Lab, who I reached by phone; he advocated that the terms copal and amber be no longer used, as I recall, due to the disinformation associated with them. Fossil resin is the preferable term. I also spoke with an entomologist at the University of Florida – can no longer remember his name – who agreed with Anderson. The term subfossil is generally not understood in the context of degree of polymerization, as in incomplete permineralization. There is no measuring stick with regards to age, or way to correlate age with polymerization. Polymerization is dependent the entire environmental history, which is unknowable. So far as I’ve been able to tell, disinformation is being propagated by a few self-proclaimed experts on the Internet, and I do not think Wikipedia should contribute to that. Please dig deeper and I think you’ll agree.SNP —Preceding undated comment added 20:40, 13 April 2011 (UTC).

The terms appear quite a bit in literature for extinct taxa described from ambers and copals [1] such as this one and this one [2]. Notably the general definition of the distinction between the two is not, as you have also noted, the degree of polymerization, but the degree of volatile terpene loss in the resin. Resins that have lost the majority of the volatile terpenes are classifies as amber while those that have a significant amount of volatile terpenes are classified as copals. If you have references that contradict the information in the article, please supply them and add them to the article with your proposed changes--Kevmin § 21:07, 13 April 2011 (UTC)

Interesting. I never looked under that lamp pole. I also was unable to follow back to when the terminology began. While it seems incongruent to me that subfossil terminology is shared by frozen mammoths and tree resin terpene content, there it is, right there in the literature. Thanks for the references.SNP (talk) 13:30, 14 April 2011 (UTC)

Copal is subfossil? I'm obviously coming at this from a different background, but I never knew that before. Maybe the article should be split? The freshly harvested resins used for incense aren't really the same thing as the subfossil stuff. Is the subfossil stuff used for incense? I'm kind of confused as to how the article has ended up focusing so heavily on the subfossil definition since it includes sources about fresh incense (e.g. [3], scroll down to footnote 1) Plantdrew (talk) 21:54, 22 May 2013 (UTC)