Amber, Preserving The Past

Holding Million Year Secrets, Amber

Most gems that we come across owe their origin and existence to various minerals. Very few gems have their origin in a living object, amber is one of them. Amber was formed from the sap or resin of certain trees, this was millions of years ago. These tree species are now extinct, the rest of the amber story sounds like a fairy tale and we will now talk about it. There are clear researched findings related to amber. Folklore and traditional beliefs do add their own flavor but, these need not distract our journey forward into this report.

Back in time around 20 to 40 million years ago, were forests with trees that dripped resin or sap from their barks. The sticky resin dripped along the bark and onto the ground below. Some of the resin got retained within the cracks and splits of the bark. As you would expect, the trees and forest ground were home to many tiny insects. Pieces of twigs and leaves also littered the forest. When the resin fell on them or dripped along, some of these objects got stuck to the sticky sap. The sap or resin, embraced these objects and held them within itself. The resin obviously dried over a period of time while, leaves, twigs and insects were forever trapped in it. This was the first step towards the resin transforming itself into amber.

The natural effects of temperature, pressure and evaporation caused the dried resin to polymerize. This is a technical word but basically what happened was that, the physical charateristics of the resin were grossly altered. The material was no longer sticky and had a better hardness as compared to resin. In normal circumstances, dried resin would have easily dissolved in solvents like alcohol, acetone or gasoline. But polymerization substantially reduced the capacity of the dried amber to dissolve in these solvents. In simple terms you could say that the dried resin which was now called amber, turned into a natural 'plastic'.

It is important to understand that, not every piece of dry resin can be called amber. Molecular polymerization is essential for resin or sap to turn into amber. This can take anywhere from hundred thousand to a few million years. You will come across 'young' amber which has not been polymerized, such material should not be called amber and is rightly called 'copal'. Solvents like alcohol, acetone and gasoline can dissolve such young amber. The solubility test is one of the methods use to segregate amber from copal. This is a destructive test and should not be tried by inexperienced hands.

Many people wonder whether amber can be regarded as a fossil. The general understanding about fossils is that, the organic material in an object are replaced by minerals. Scientists refer to this as mineralization and it is not relevant in the case of amber formation. We just explained that amber is formed by the polymerization of resin and not by mineralization. Once you have this basic understanding, you could refer to amber as a fossil after all the word polymerization is not easy to remember or spell!

Now let us come to the objects that get trapped in amber. These leaves, twigs, insect parts or whole insects had their existence during the time that the sap dripped from the trees. That was millions of years ago, most likely 20 to 40 million years ago. These leaves or insects are now extinct and we could never have seen or learnt about them had they not been trapped in the amber. Many amber findings have maintained these inclusions in great structure and form, it is as if they are frozen in time. They are therefore a good source of evidence to scientists studying the history of our planet including the trees and creatures that once lived on it. To gem lovers, the fascinating but true story, enhances the meaning and value of amber.

As a gemstone, amber is not very hard and measures within the 2-3 reading of the Mohs scale. Natural amber is sensitive to heat so should be kept away from heat sources. Though the solubility of amber in acetone, alcohol and other solvents is substantially reduced, you would do good to keep your amber jewelry away from such materials.