The most widespread copals are named after either their locality or their parent tree:
Modified Colombian copal
Copal - tree resin (coniferous or deciduous species), occurring in different varieties in the subtropical countries.
Copal was a popular material for jewellery and figurines among many peoples of the world. Currently, it is also used
in professional jewelry.
The term copal comes from a language of Aztesc and means resin juices. But kauri copal or Manila copal are quite different from copal found in Colombia or South-Eastern Asia. Zanzibar copal is also quite different. Copal from Mizuni (Japan)
is referred to as amber and contains many organic inclusions, just as the copal from northern Madagascar. Since 1981, collectors have also been familiar with copal from the Dominican Republic, found in Cotui, Bayaguana region. The age of this copal has been radiocarbon dated to be only 300 years, although other Dominican resins (also described as copal) from Bayaguana have been attributed the age of 15–17 Ma.
There is an on going discussion in science literature on what should be referred to as copal. Age is the most frequent criterion. Some place copal’s age between 10,000 and 5 million years and therefore classify Africa’s Pliocene resins as copal as well. Others would much rather use theterm copal to describe resins from the last million years or from the Pleistocene atmost. According to D. Schlee, the term copal is even used for a group of resins that are less than 250 years old. This name is sometimes used interchangeably with the name "resin" to describe both contemporary copal and that older than the Pleistocene. On the other hand, in New Zealand a Palaeogene fossil resin is referred toas kauri copal. Some believe that until there is a precise definition of copal which is not related to a specific age it is best to use the convention of applying the name copal to Pleistocene resins which are less than one million years old.
The properties of copal, including its lower melting point, lower hardnessand good solubility, differ from the properties of Baltic amber and therefore help in identifying copal. A few drops of acetone make the surface of copal sticky. It can also be rubbed with a cotton pad soaked in ether which will leave a matt smear or stick to the surface. It is much different with amber: rubbed with ether, it will only show slight changes on its surface after two weeks. Copal is colourless, with its surface layer sometimes darkened. For production purposes, copal can be aged to become light yellow and light brown. The German market contains a wide range of products made of copal from the Southern Hemisphere which is an excellent imitation of amber, especially when an extra layer of varnish is applied to it properly.
Copal from Cotui