AMBER - What is amber?

Fossilized resin from trees. It is composed of complex organic material without any definitive chemical formula.
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Amber is neither a gemstone nor a mineral, but an organic material which, through millions of years of hardening, has reached a fairly stable and solid stage. Amber has an amorphous structure, which means that its chemical composition and physical properties will vary from piece to piece.
The basic ingredients are carbon (approximately 78%), oxygen (11%) and hydrogen (10%) and the chemical formula is written as C10H16O, but due to its amorphous structure, it may vary depending on the type of amber. Judging from its chemical structure, amber is very similar to the plastic of our time.

The moment the resin ran out of the tree trunk, the curing process began. Factors that are important for a good curing process of amber are i.a. oxygen-free conditions, protection against UV light and the pressure from the surroundings. There are several stages between resin and amber - the best known is called copal. It is a stage where the resin is hardening and has not yet turned into amber. Depending on how early the resin is in its curing process, it may have a more or less sticky or 'soft' consistency.

Different types of amber come from different trees, therefore each type is chemically different, and since the resin has also been preserved under different geological conditions, the speed of when the resin reaches the individual stages is also different. The whole process from resin to amber takes about 12-20 million years depending on the type. Once resin has reached the stage of amber, it can, if its journey is not disturbed, reach an age of several hundred million years.

Physical attributes of most amber

Hardness: 2.0 - 2.5 (Mohs scale)
Refractive index: 1.5 - 1.6
Specific gravity: 1.06 - 1.10
Melting point: 250–300°C. If the amber is heated above 200 °C, it will slowly break down. It will secrete an oil and leave behind a black residue known as "amber colophony". When this is dissolved in turpentine oil or in linseed oil, it forms "amber varnish". If the amber is pressed together under high temperatures and pressure, you can create the product "pressed amber". Small pieces of amber that merge and form larger pieces of amber - read more about this in the section forgeries and imitations

Amber - this almost magical material acts as a message in a bottle sent into the future and has preserved and maintained moments of the past in 3D. When studying the world in amber, your traveling back in time, and in the most literal sense studing the past almost as if you walked in the endless forest million of years ago. Amber and its importance to the understanding of life and the evolution of the earth is deeply underestimated by the general public.

The oldest amber in the world originates from the United States and has an age of as much as 320 million years. The oldest amber found at the time of writing with inclusions (a fly and two mites), originates from the Alps in northern Italy and is 230 million years old. Jordanian and Lebanese amber is the oldest amber that has been found, where due to the frequency of the inclusions it has also been possible to obtain a more systematic insight into the biodiversity of the old primeval forest. This amber is 125-130 million years old, but at the time of writing is unfortunately difficult to access due to minefields and political instability. Most of the types of amber we know of were created in the period 130 million years ago and up to the present day. The largest occurrence of all types is Baltic amber, which has an age of about 34-48 million years - it is this type that is found in Denmark. It is said that well over 80% of all the amber we know in the world is Baltic amber.

There are more than 150 different types of amber in the world, and each type acts as a portal back in time. That means that the last approx. 135 million years of the history of the earth is to a greater or lesser extent archived in the amber. Through this website you will be able to go on a time trip and with your own eyes see how life looked millions of years ago.

Picture: Otto Frello, 'Oksbølbilledet' / The Baltic amber forest

- this is an introduction to the colors of amber and not a review of every single cause of each color

Each piece of amber is completely unique. It was created in an ancient forest, by trees that are long extinct and have had a journey through time and place for millions of years, which all has affected it. This has created a huge color range between the types and also within each type. The colors of each piece are first and foremost affected by which tree that produced the resin, then the color is affected by what the resin has been exposed to, on its way down the tree and then the many millions of years under different geological circumstances.

Many people know the yellow, orange and red shades of amber - they are also the most pronounced and are repeated in different shades in almost all types of amber. But there are also types that do not have these nuances - e.g. Indian amber is naturally greenish. The colors are in most types combined with different clarity, which is created by e.g. inclusions or air bubbles. A high concentration of air bubbles will e.g. catalyze a whitish shadow with different densities depending on the amount of small air bubbles. And something like plant debris will in high concentrations often create a dark tone in the amber.

The reddish hue is created by oxidation - when the amber meets the oxygen of the atmosphere, it will go into a chemical process and breaks down. The degradation is very slow and will primarily be expressed in a deep red tone. The more the amber is exposed to oxygen the deeper will the red color be. In the jewelry industry, this color is coveted, but if one studies inclusions in amber, then this will be the color one will avoid as the inclusions also will be degraded in the oxidized amber.

So to summarize - The various reasons have together played a role in the creation of the color shades of each piece - e.g. the combination of heavily oxidized amber with many inclusions will create a very dark piece of amber, or if the resin has run down the tree trunk without any thing to affect it and if the same piece has laid protected from oxygen in the ground, then it will appear as the basic color of the type of amber - e.g. Baltic amber will most likely appear in a

shade of yellow.

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As the last thing and an absolutely central thing is, how each piece of amber has been handled by humans through the years. If it has to a large extent been exposed to the UV light of the sun, then the piece will to a greater extent have small cracks in the surface. If the piece has not been in contact with human skin for a long time, then it will not have received the fat from the skin that will protect the surface from the oxygen of the atmosphere and the piece will be more oxidized ect. Many things come into play when it has been brought out of its protective element in the earth, which has provided a fairly static protection over millions of years. Finally the amber can also be treated in different process by humans and the color and appearance of the amber can be changed deliberately.

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So as you can sense, there are several circumstances that play a role in the color and appearance of each piece - first of all, each type has its basic colors and then it has its typical combinations of shades and in addition its more rare deviating shades. Types can be reminiscent of each other but for someone who knows the amber, they can easily be known from each other.

Initially I would just like to mention that in the same way that there is amber with a blue tinge, there is also amber with a green tinge - this is due to the same phenomenon as with the blue amber. The chemical reason for its occurrence is often explained by the fact that some pieces of amber from types such as Dominican, Mexican, Burmese and Indonesian amber have a high content of hydrocarbons.

The hydrocarbon content of these pieces absorbs the energy from the natural UV light of the sun, and re-emits the energy as visible light - the re-emitted light is at a lower frequency than the ultraviolet light of the sun, and when the amber reflects the light, the "luminous" blue color occurs. If the amber is on a light surface, the light background reflects to a greater extent, and you will therefore not be able to see the reflection of the amber. If it lies on a dark surface, the reflection of the amber will be clear and the blue glow will occur.

The light phenomenon is due to energy transfer. An electron absorbs a photon from the sun with high energy and is lifted to a higher energy level. The electron has been excited (estimated or activated). The system returns to the ground level by emitting a photon. The outgoing photon will always have lower energy than the incoming photon, i.e. the outgoing radiation will always have a longer wavelength than the incoming radiation and this means that the color of the light will also be different.

Some researchers believe that the conditions in the forests of that time are the reason why some pieces from certain types of amber are fluorescent. They believe that it is forest firewood that has deposited the particles in the resin, and therefore there are some pieces from that type that have the bluish tinge. That should probably be correct, but the final answer to why some pieces light up is probably more complex than that. Baltic amber appears e.g. not as strong blue as some pieces of Dominican amber, despite the fact that there was probably also forest firewood in the Baltic amber forest. And in addition, some types generally shine brighter in UV light than others.

Picture of green/blue piece of Dominican amber made by Géry Parent