Copal and Amber: A Comparison

Amber and copal are often mistaken for each other, and the confusion is not entirely innocent — copal has been sold as amber for as long as both have been valued, because at a glance, freshly polished, they can look nearly identical. The honest difference between them is mostly a matter of time: copal is tree resin on its way to becoming amber, not yet finished, anywhere from a few centuries to a few hundred thousand years old; true amber, Baltic amber especially, has had tens of millions of years to complete a chemical process copal has barely started.

That incomplete process is also how you tell them apart without a lab. Amber is fully polymerized — its molecular chains have long since finished cross-linking into something chemically stable and largely inert. Copal hasn’t finished the job, which means a drop of acetone, or even firm rubbing with an alcohol-soaked cloth, will soften or dissolve its surface, leaving it slightly tacky; the same test does essentially nothing to real amber. It is the standard field test jewelers still use, and the standard trick that has let copal pass as “young amber” for a very long time.

The two materials also carry different weight culturally. Amber’s story runs mostly through Europe — the Amber Road, Baltic trade, Roman collectors. Copal’s runs mostly through Mesoamerica, where the Nahuatl word copalli simply meant incense in general, and where the Maya and Aztec burned it in enormous quantities as a central part of religious ritual, long before either culture had any contact with the Baltic coast or its much older resin.