Although not mineralized, amber is often considered a gemstone and has been included in many pieces of jewellery throughout the ages. Amber is actually fossil tree resin, which is the semi-solid amorphous, organic substance that is secreted in pockets and canals through the plant. It is not (as it is often assumed to be) tree sap.
Amber occurs in a range of different colours, varying from a whitish yellow through a pale lemon shade to a brown, almost black variety. More uncommon colours include red (or cherry) amber, green amber and even blue amber, a rare and sought after colour choice.
About 92% of the world's extractable amber is located in the Kaliningrad region of Russia on the Baltic Sea. Most amber dates from between 35 to 40 million years ago. Some amber is considered to be up to 345 million years old