Amber is a fossilised resin from ancient conifer trees. It usually occurs in a colour range from pale yellow or orange to brown. Rarer types include the cloudy white or 'bone' amber, and various shades of green and blue. Amber has been used in jewellery since prehistoric times.

Some Unusual Properties of Amber

Amber is quite soft. On the 1-10 Moh hardness scale (where quartz is 7 and diamond 10), amber has a value between 1.5 and 2.5. This means that it can be cut fairly easily, even with very primitive tools. On the other hand, the surface can be easily scratched. It is difficult to cut amber into sharp facets, so it is usually polished into round surfaces. The density of amber is not much greater than that of water. It doesn't actually float, but small lumps are very easily rolled and moved in seawater. This is why in the Baltic region amber pebbles were often found washed up on beaches.

Amber is a poor conductor of heat, which means that it feels quite warm to touch. It is also a poor conductor of electricity. The ancient Greeks noticed the way that amber could develop a static charge when rubbed. Their word for amber electron gave rise to our modern name for electricity. Amber will melt at temperatures above 250-350°C and will burn at higher temperatures. It can be dissolved in a range of solvents. In the 19th Century, a lot of poorer quality amber was dissolved in this way and was used in making varnishes.

The Baltic Amber Forest

The world's most important deposits of amber are found in the Baltic region. Around 35 to 40 million years ago, a huge coniferous forest covered the area of what is now Scandinavia, and extended into what is now the Baltic Sea. At the time, the climate was sub-tropical. These trees produced large amounts of resin, probably as a defence against insect or fungal attack. Lumps of resin caught in sediments were gradually fossilized into amber.

Much of this amber was washed southward, and ended up as a secondary deposit in the 'Blue Earth' layer in the Samland Peninsula, near Kaliningrad (formerly Köningsberg). This is the main source of Baltic amber today, as the Blue Earth layer has been extensively mined. Since the Blue Earth deposits stretch out under the Baltic Sea, they are also the source of most of the amber washed up on beaches from Estonia to Britain.

Other Sources of Amber

The Dominican Republic is now the world's second most important supplier of amber. The rock layers involved are mostly younger than those of the Baltic deposits, from as recently as 10 million years ago. There are some deposits of an unusual cherry-red amber in Burma, which traditionally was used in China.

Insects and Inclusions

Large numbers of trapped air bubbles give some kinds of amber a cloudy appearance. Far more important are the trapped items or inclusions, in which leaves, insects and very rarely even lizards, frogs and feathers, are preserved in a glass-like amber shell. These fossils can offer a lot of information about the ecology of the original forests. Speculation that DNA could be recovered from these inclusions inspired the book and film Jurassic Park. Unfortunately, the Dominican Republic amber featured in the film is far too young to have traces of dinosaurs, and more recent research has cast doubt on the chances that DNA could last that long.

Baltic Amber through the Ages

Prehistoric and Ancient Times

While some pieces of early worked amber have been found, actual trade routes for Baltic amber seem to have developed in Europe in the Bronze Age, from as early as 3000 BC. One Polish site dated to 2000 BC contained 30,000 pieces of worked amber.

At various times, the Phoenicians, the Etruscans, the Greeks and Romans all took an interest in trading and collecting amber, and it has been found in many famous ancient sites, from Tutankhamun's tomb to Schliemann's excavation of Troy. After the fall of the Roman Empire, the amber trade continued, and there are many examples of Celtic, Anglo-Saxon and Viking amber pieces.

The Teutonic Knights

In the late 13th Century, the Teutonic knights obtained a monopoly on amber production in the Baltic region, with a complicated system of licensing. Collecting amber on beaches without a licence could bring a death sentence, with unauthorised collectors being hanged. Under the knights, most of the amber was used in making paternoster beads, strings of prayer beads which were an earlier version of the modern Catholic rosary beads. For many years, they kept the city of Köningsberg as a mining centre only, but gradually it became a centre for amber working as well.

The Prussians and the Russians

After the Reformation, the Samland Peninsula and the city of Köningsberg became part of East Prussia, and the Prussian rulers kept a tight monopolistic control on the amber trade. By the 19th Century, production was on an industrial scale. Much of the output from the Köningsberg mines was used in making varnish.

Köningsberg became part of the USSR in 1945, and was renamed Kaliningrad. In the Soviet era, the production and the export of amber was tightly controlled. After the break up of the USSR, Kaliningrad remained part of Russia, but amber is now extensively traded from the Kaliningrad mines to neighbouring Poland and Lithuania, both of which now produce large quantities of worked amber.

The Mystery of the Amber Room

In 1701, Friedrich I of Prussia commissioned what became known as the Amber Room, which contained more than 100,000 pieces of carved amber panelling, with a total area of 55 square metres. His heir, Friedrich Wilhelm I, presented it to the Russian Tsar, Peter the Great, in 1717. First set up in the Winter Palace in Saint Petersburg, the Amber Room panelling was moved to the Catherine Palace at Tsarskoe Selo in 1755, where it stayed for nearly 200 years. In 1942, the amber was stripped from the palace and taken to Köningsberg by German soldiers. It was last seen in Köningsberg castle in April 1945. It was probably destroyed in a fire in the castle soon afterwards, but some people claim that the crates of amber still exist in some hiding place. Since the amber could be valued at more than €280 million, this mystery still attracts a lot of interest.

Some Places to Visit

There are a number of amber museums in the Baltic region. The Swedish Amber Museum in Höllviken has an interesting website. The amber museum in Palanga in Lithuania is said to have the largest collection in the world, with over 25,000 pieces of amber. The Malbork Castle Museum in Poland, located in an old castle of the Teutonic Knights, also has a famous collection. The European Amber Road website gives details of many other interesting museums.