Amber is an organic material composed of fossilised tree resin. The resin is produced by trees as a defence against disease and insect attack. Whilst most gem ambers are between 15 million and 40 million years old, some ambers have been found to be as old as 300 million years.
Origin and value
Most amber today is found in Northern Europe around the Baltic Sea. Other important sources are the Dominican Republic and Mexico. In recent months the value of amber has risen again to a point where some specimens are selling for the same price, gram for gram, as pure gold. Caution is required however, as not all examples are as they seem.
Smaller pieces of amber are sometimes heated and pressed together to form larger blocks known as pressed amber. Cloudy amber can be heated to force out the tiny bubbles and make it transparent. The colour of amber can also be darkened through heating and some specimens have even been coated to improve durability.
There are also a whole host of other materials commonly used to imitate amber. Glass is easy to differentiate as it is much denser, much harder and feels colder to the touch than amber. Plastic can be more convincing, but again, is usually denser than amber and gives off an acrid, plastic smell when touched with a hot needle. One much harder imitation to spot is copal. Copal is a younger resin but has similar physical and chemical properties. It is however generally a lighter, more golden colour, crazes more readily and can give off a pine smell when rubbed or scratched. This smell is from plant oils within the resin which have not yet evaporated off, something which would have occurred long ago with amber.
Insects trapped inside a material were once seen as proof that the material was amber. It is now known that insects can be found inside younger copal specimens and also artificially embedded into plastics. When introduced in this way, the insects often do not show the signs of struggle sometimes seen with those who have become trapped in amber. The lack of such evidence should only be used as an indication however, rather then proof. Another common inclusion is the ‘sun spangle’ or ‘lily pad’ stress cracks caused by the rapid cooling of heated amber. Sometimes these inclusions are induced deliberately for their attractive qualities.
If you have any amber which you would like to have valued, please contact Simon Rufus, jewellery specialist at Grand Auctions, Folkestone, Kent.