Properties of Baltic Amber

Gabriela Gierlowska

Baltic amber (succinite) is a fossil resin which formed under natural conditions 45 million years ago. In spite of the many processes, which the resin went through to transform into amber, it remains in the fossil stage, i.e. is subject to oxidising and polimerisation. Since this process is ongoing, amber keeps changing so we can assume that it is a “living” stone, friendly to humans. Our forebears were interested in amber and used it for their purposes as early as in the 13 th millennium BCE. It is from that period that what we now consider to be the earliest simple drawings of predators and wild horses made in amber originate; the artefacts were found in Meindorf, Germany and Siedlnica, Poland.

And so, this unique stone has been fascinating humankind for well over a dozen millennia and has been a material for craft and art, as well as a stone thought to have magical and medicinal properties. Today, amber adorns most of the silver jewellery produced in Poland , which is exported throughout the world.

  • Amber is light, its density is comparable to that of seawater and ranges from 0.96 to 1.096 g/cm 3. This is a key practical benefit, because it means that large amber jewellery, such as necklaces, pendants and earrings, can be easily made and comfortably worn.
  • Amber is the only fossil resin to contain 3-8 % amber acid, a medicinal substance with diverse effects; most of the amber acid is in the amber's crust, i.e. its surface layer.
  •  Amber floats on salt water, while in fresh water it usually sinks. When it appeared after storms on the waves of the cool Baltic and North Sea ages ago it never failed to intrigue and suggested a great supernatural power inherent to it. It still happens today: when the weather is cool (March, November) and the water temperature is around 4°C and its density at its peak, the undulation of the sea causes the amber to come up from the seabed and the waves wash it onto the beaches.
  •  Baltic amber is found in the following deposits: in the Gulf of Gdansk area - in the Sambian Peninsula, Russia, and at the base of the Hel Peninsula, Poland (these are the richest amber deposits in the world), as well as in the Lublin region in the area of Lubartow, Poland, in the Polesie area of the Volyhn Region (Ukrainian amber) and in Bitterfeld, Germany (Saxon amber). It is deposited at a depth of several to about 150 metres.
  •  Raw amber comes in diverse forms (e.g. drops , icicles, dripstones) and nuggets of various sizes, which show how it was formed and how it travelled. (see: The Origin of Baltic Amber)
  • Amber has a great diversity of colour varieties: from white, which was the most greatly valued centuries ago, through all kinds of shades of yellow and brown to a unique red. Amber also comes in shades of blue, green or even black. We differentiate primary and secondary amber colours. (see: Varieties of Baltic Amber)
  •  Amber often contains organic inclusions: insects, arachnids, myriapods, small amphibians, plant remains, grains of sand and gas bubbles. They are a source of information about the time when amber was formed, the animals which lived in the proximity of resinous trees or were active when the resin flowed out. "Gierlowska Lizard" which is kept in the collection of the Amber Museum in Gdansk, is an example of a unique inclusion in a natural Baltic amber nugget.
  •  Amber's value generally depends on the size of the nugget, but the decisive factor is the principle – known to amber jewellers who would haggle over the raw material ages ago – which says that “nuggets equal in weight do not have the same price, which depends on purity, clarity, rarity and refinement of colours ” (J. Grabowska).
  •  Amber nuggets are warmer than other stones and when rubbed, they attract bits of dry grass and paper, as amber becomes electrically charged. It charges negatively, which is beneficial for people.
  •  Amber's thermal and electrical conductivity is low and isotropic, i.e. the same in all directions.
  • Amber nuggets burn when lit, with a bright yellow flame, exuding a pleasant resinous scent. Pliny wrote: “Pieces of amber, steeped in oil, burn with a more brilliant and more lasting flame than pith of flax.”
  •  Amber is very heterogeneous in terms of its chemical makeup.
     It consists of:
     C (carbon) – from 61 to 81%
     H (hydrogen) – from 8.5 to 11%
     O (oxygen) – about 15%
     S (sulphur) – about 0.5%; as a secondary ingredient it can reach a volume of up to several percent.
     Amber also contains other trace elements and minerals.
  •  Amber cannot be fully made into a solution. It partially dissolves in certain organic compounds: 20-15% in methanol, 18-23% in ether, 20.6% in chloroform, 21% in benzene, 25% in turpentine.
  •  Amber's hardness on the Mohs scale is from 2 do 3, while its microhardness ranges from 19.9 to 29 kg/mm 2 . This depends on the variety: bone amber has a microhardness of 19.9 kg/mm 2 , transparent amber 26.2 kg/mm 2 , weathered amber 27 kg/mm 2 . The microhardness range in a single nugget can be as broad as ± 5 kg/mm 2.
     Amber has a diverse internal structure, mainly porous or foamy, but it can also be solid. Porous and foamy structures come from gas bubbles, whose number and placement in the nugget determine its degree of transparency and colour. But, as the most recent research on amber's structure has revealed, that's not all.
  •  Curiously, a structure of very thin layers has been discovered in transparent amber nuggets. The same goes for the crystalline phase, where the discovered crystals are of varied tabular or rod-like habit, or are even bent fibrous crystals, and “ occur on the insides of gas bubbles, much like the quartz lining found inside oval geodes” (B. Kosmowska-Ceranowicz).
  •  Amber has a distinctive conchoidal (shell-like) fracture.
  • When scraped, amber's surface shows a light-coloured scratch and fine chips.
  • Amber undergoes weathering processes which take place both in the sediment and out of it, once the amber has been excavated. In the past, raw amber was kept in brine to protect it from weathering. Today, protective synthetic wax mixtures are used, as well as dammar resin or amber colophony solved with gum turpentine to soak the amber in.
  •  Amber changes mainly due to the impact of light. To begin with, its surface darkens and it gradually loses its luminosity and transparency. As the exposure time lengthens, the surface turns rough. The next stage is when fine cracks appear, alongside with scales which flake off even when moved only slightly, and then this layer is lost.
  • Subject to dry distillation, with no access to air in heated retorts, amber yields: amber acid, oil and colophony, which are used in medicine and as high-quality impregnant, lacquer and varnish ingredients.
  • Amber is easy to work: it can be ground, cut to pieces, sculpted, engraved, made into intaglios and cameos.
  •  Amber cooked in vegetable (almond or rapeseed) oil becomes soft and pliable.
  • When heated rapidly, amber breaks. Amber's softening point is ca.150°C; its melting point - 300°C.
  • Amber can be dyed with natural substances, such as the plant extract of Anchusa tinctoria , Phoenician purple and goat fat, which was documented by Pliny the Elder, as well as with synthetic dyes.
     Today, amber which is used in the jewellery business is very often improved. The improvement process takes place in autoclaves filled with inert gas under high pressure to clarify, harden or change the colour of amber. Through this process we can obtain: fully transparent nuggets, completely unified pieces of layered amber, forgeries of amber inclusions (when an insect, feather, shell or plant fragments are placed between 2 pieces of amber; after treatment, the new piece bears no trace of being joined), surface colour or colour unification.
  • Amber pressing is also possible; it involves combining fine amber pieces or even amber powder into larger pieces under pressure. In this way amber material, with structure dependent on the technology used, is formed. In the 19 th century, amber pressing methods were patented and named after their developers: the Spiller method and the Trebitsch method. Today, technological progress has made it possible to make products out of pressed amber which are very difficult to tell from pieces made of natural amber nuggets.
  •  Gemmology and jewellery studies define amber's sheen as greasy or waxy. After improvement processes, amber has glassy sheen.
  • The refractive index of amber is 1.539 – 1.542. For reference: in the case of glass, which the first amber imitations were made of, this index is 1.420 – 1.960.
  • Amber research and identification is difficult as amber does not dissolve fully in any currently known solvent. FTIR Spectroscopy is an effective and reliable method, where a section of the curve called “the Baltic arm” formed in the 1200-1260 cm -1 band range is the diagnostic determinant.
  • Natural amber – which has not undergone any processing, but has only been ground of its crust and polished – is alive, as the process of its internal transformations continues and it is beneficial to human beings.

Personally I'm convinced that this stone brings good luck. It supports and enhances positive energy. Amber stabilises and reconstructs our natural electrostatic field, which is disturbed by omnipresent computers and mobile phones.

Amber is extraordinary and mysterious. But it is also fascinating and beautiful in that it lets us enjoy it and discover its secrets.