Amber is the fossilized resin secreted from trees. Living things imprisoned millions of years ago inside the resin secreted from trees in the Dominican forests have been preserved in exactly the same form right down to the present day by literally being mummified as the resin solidified.

In chemical terms, resin is made up of different organic substances. It is insoluble in water but solidifies very quickly in contact with the air. The polymerization process (monomer molecules entering into chemical reaction in order to give rise to three-dimensional chains) begins and the resin remains in solid form for millions of years.  Any living thing that resin pours over remains in that exact same form, totally unchanging, for millions of years.