The Aztec word “copal” (Nahuatl: copalli) refers to all tree resins -old or young- that have been employed as amber incense over the centuries. Consequently, from this etymological point of view, it turns most ambers, also the ‘famous’ Baltic or the almost equal old Dominican amber, into Copal, because they are used for incense even today. LOL.
But for lack of a better word, in modern times “Copal” is used to refer to semi-fossilized amber resins or sub-fossil amber. Basically, “copal” is “young amber” and amber” is “old copal”.
Where is the age limit? There is much theory and commercial interest. Some set the limit at 20 million years, others earlier.
Fact is, we have no dates or specific geological information on Colombian copal or Colombian amber. Because of it’s color and hardness, some scientists believe it may be Pliocene or Pleistocene, probably about 2 to 3 million years old, in some regions even up to 16 million years old, but in others much, much younger (Santander) and may only count with some thousands, or some hundreds of years.
But opinions, theories and scientific researches and their methods vary. For example, Terrance M. Allen (Entomologist, Archeologist, Practicing Paleontologist, and Factotum Naturalist ) writes: “I believe, based on the fact that stellate oak (floral) hair (Family: Faqaceae, Genua: Quercus sp.) was discovered in Colombian copal/amber by this author (T.M. Allen, April 2010), and that stellate oak hair is used as an indicator fossil species found in Dominican Amber, Chiapas (Mexico) Amber, and Baltic Amber scientifically aged to be 20 million, 25 million, and 40 million years old respectively, that some Colombian copal / amber can be dated to be approximately 20 million years of age and can be termed to be true fossilized “Colombian Amber”. (Or too, maybe stellate oak hair is a more recent product of the flora kingdom than originally thought.) All debates aside, about whether “fossilized” tree or plant resins from different or designated localities around the world should be termed “amber” or “copal”, as long as it is qualified and recorded as to where the samples of prehistoric resins originate, the arthropod (and other faunal) and plant inclusions are all valuable scientific specimens and are direct evidence and indicators as the the history and evolution of life on Earth”. (T.M. Allen) May 3, 2010. Revised November 30, 2010.