Because it originates as a soft, sticky tree resin, amber sometimes contains animal and plant material as inclusions. Amber is globally distributed, mainly in rocks of Cretaceous age or younger. Historically, the coast around Königsberg in Prussia was the world's leading source of amber. About 90% of the world's extractable amber is still located in the Kaliningrad Oblast of Russia on the Baltic Sea. Pieces of amber torn from the seafloor are cast up by the waves, and collected by hand, dredging, or diving. Elsewhere, amber is mined, both in open works and underground galleries. Then nodules of earth have to be removed and an opaque crust must be cleaned off, which can be done in revolving barrels containing sand and water. Erosion removes this crust from sea-worn amber. Heating amber will soften it and eventually it will burn.
Amber occurs in a range of different colors. As well as the usual yellow-orange-brown that is associated with the color "amber", amber itself can range from a whitish color through a pale lemon yellow, to brown and almost black. Other more uncommon colors include red amber (mainly from the Arabian Peninsula), green amber (from the Baltic and Dominica ), and even blue amber (especially Dominican blue amber), which is mined through bell pitting, which is dangerous due to the risk of tunnel collapse. Dominican amber is also fluorescent in long-wave UV light and has a very strong reflection, almost white. Much of the most highly-prized amber is transparent, in contrast to the very common cloudy amber, which is many times called"butterscotch amber". Opaque amber contains numerous minute air bubbles. This kind of amber is known as "bony or white amber".
Rare Blue Amber from the Dominican Republic
Copal is a name given to tree resin that is particularly identified with the aromatic resins used by the cultures of pre-Columbian Mesoamerica as ceremonially burned incense and other purposes. More generally, the term copal describes resinous substances in an intermediate stage of polymerization and hardening between "gummier" resins and amber. Copal has been found to be a young a several hundred years, but most of the true Copal is considered to be 1.5 to 3 million years old. The word copal is derived from the Nahuatl language word copalli, meaning "incense".
To the pre-Columbian Maya and contemporary Maya peoples it is known in the various Mayan languages as pom (or a close variation thereof), although the word itself has been demonstrated to be a loanword to Mayan from Mixe-Zoquean languages. Copal is still used by a number of indigenous peoples of Mexico and Central America as an incense and during sweat lodge ceremonies.
Kauri Gum is a fossilized resin detracted from kauri trees and used for chewing, tattooing, and were often made into jewellery. The gum came from kauri trees found in forests that once covered much of the New Zealand North Island, before Māori and European settlers caused deforestation, causing several areas to resort to sand dunes, scrubs, and swamps. The ancient kauri fields continue to provide a source for the gum. Kauri gum formed when resin from a kauri trees leaked out through fractures or cracks in the bark, hardening with the exposure to air. Lumps commonly fell to the ground and became covered with soil and forest litter, eventually fossilising. Other lumps formed as branches forked or trees were damaged, which released the resin. Kauri gum is the youngest of the fossel resins, some being less than 50 years in age.