Genuine amber may also have been modified to clarify or colour it, or pressed and extruded to make larger articles from small pieces. Several tests are described in the references below which may distinguish the various substances if applied carefully. A common form of fake amber is the phenolic resin bead necklace, usually quite large and possible as old as 1900's. Amber is a natural organic material and must therefore be treated more carefully than most gems. It is easily scratched and may be brittle, especially if it contains natural fractures.
Organic solvents can cause surface damage as can heat and bright light.
Amber from some localities is more prone to surface crazing than others and will inevitably deteriorate with time. Wearing amber jewellery is supposed to preserve its appearance due to the continuous polishing and adsorption of skin oils. Some older specimens may have been surface treated to improve clarity by coating with some form of oil or lacquer. Van Nostrand Reinhold. Butterworths gem books.