amber, inclusions, gems

Gübelin and Koivula examine the diverse inclusions found in amber, extending attention beyond the familiar plant and animal remains to the less frequently discussed inorganic and fluid features. The article illustrates insects and other organic inclusions together with gas bubbles, liquid-bearing cavities and other structures preserved in fossil resin. Particular attention is given to the processes by which inclusions became trapped and subsequently preserved and to microscopic features that provide information about the history of the resin. Examples include cavities interpreted as gas or air bubbles and two-phase inclusions possibly representing droplets of water with contraction bubbles. The text corresponds closely to the amber section of the authors’ 1986 Photoatlas of Inclusions in Gemstones, although some of the photographs differ.