Amber is found in deposits of different ages. Well-known amber finds occur already in strata of the Mesozoic Era. However, the most important sources are deposits of the Tertiary Period. Baltic amber also belongs to this period, having been formed during the Eocene and Oligocene Epoch. Thus, our amber is about 30-40 million years old. Resin was also exuded by plants of the Palaeozoic Era, and some of this also fossilised, but since the fossilisation process has continued for a long time, the resin has carbonised and merged with coal. In the Quaternary Period too, in places with suitable climatic conditions, resin has been fossilised. However, this resin does not yet display all the characteristic properties of amber, and so is called copal, dammar or kauri.