Amber pendants made of modified amber. The oval pendant is 52 by 32 mm (2 by 1.3 inches).
Worry beads (masbaha) made of Dominican blue amber.
An ant inside Baltic amber
A mosquito and a fly in this Baltic amber necklace are between 40 and 60 million years old
A spider trapped in amber
The Amber Room was reconstructed from the Kaliningrad amber.
Violin bow, with frog sculpted from Baltic amber
Unpolished amber stones
Wood resin, the source of amber
Extracting Baltic amber from Holocene deposits, Gdansk, Poland
Unique colors of Baltic amber. Polished stones.
Fishing for amber on the coast of Baltic Sea. Winter storms throw out amber nuggets. Close to Gdansk, Poland.
Amber (or, technically, resinite) is fossilized tree resin (not sap), which has been appreciated for its color and natural beauty since Neolithic times. Amber is used as an ingredient in perfumes, as a healing agent in folk medicine, and as jewelry. There are five classes of amber, defined on the basis of their chemical constituents. Because it originates as a soft, sticky tree resin, amber sometimes contains animal and plant material as inclusions.
History and etymology
The English word amber derives from the Arabic ‘anbar, via Medieval Latin ambar and Old French ambre. The word originally referred to a precious oil derived from the Sperm whale (now called ambergris). The sense was extended to fossil resin circa 1400, and this became the main sense as the use of ambergris waned. The two substances were confused because they both were found washed up on beaches. Ambergris is lighter than water and floats; whereas amber is lighter than stone, but not light enough to float. The word “ambar” was brought to Europe by the Crusaders. In French “ambre gris” was then distinguished from “ambre jaune”: ambre gris was ambergris; ambre jaune was the fossil resin we now call amber.
Amber is discussed by Theophrastus, possibly the first historical mention of the material, in the 4th century BC. The Greek name for amber was ηλεκτρον (electron) and was connected to the Sun God, one of whose titles was Elector or the Awakener. The modern terms “electricity” and “electron” derive from the Greek word for amber.
The presence of insects in amber was noticed by Pliny the Elder in his Naturalis Historia and led him to the (correct) theory that at some point, amber had to be in a liquid state to cover the bodies of insects. Hence he gave it the expressive name of succinum or gum-stone, a name that is still in use today to describe succinic acid as well as succinite, a term given to a particular type of amber by James Dwight Dana (see below under Baltic Amber).
Heating amber will soften it and eventually it will burn, which is why in Germanic languages the word for amber is a literal translation of burn-Stone (In German it is Bernstein, in Dutch it is barnsteen etc.). Heated above 200°C, amber suffers decomposition, yielding an “oil of amber”, and leaving a black residue which is known as “amber colophony”, or “amber pitch”; when dissolved in oil of turpentine or in linseed oil this forms “amber varnish” or “amber lac”.
Amber from the Baltic Sea has been extensively traded since antiquity and in the main land, from where amber was traded 2000 years ago, the natives called it glaes (referring to its see-through similarity to glass).
The Baltic Lithuanian term for amber is Gintaras and Latvian Dzintars. They and the Slavic jantar are thought to originate from Phoenician jainitar (sea-resin). However, while most Slavic languages, such as Russian and Czech, retain the old Slavic word, in the Polish language, despite still being correct, jantar is used very rarely (even considered archaic) and was replaced by the word bursztyn deriving from the German analogue.
Composition and formation
Amber is heterogeneous in composition, but consists of several resinous bodies more or less soluble in alcohol, ether and chloroform, associated with an insoluble bituminous substance. Amber is a macromolecule by free radical polymerization of several precursors in the labdane family, e.g. communic acid, cummunol, and biformene. These labdanes are diterpenes (C20H32) and trienes, equipping the organic skeleton with three alkene groups for polymerization. As amber matures over the years, more polymerization takes place as well as isomerization reactions, crosslinking and cyclization.
The average composition of amber leads to the general formula C10H16O.
Molecular polymerization, resulting from high pressures and temperatures produced by overlying sediment, transforms the resin first into copal. Sustained heat and pressure drives off terpenes and results in the formation of amber.
Fossil resins from Europe fall into two categories, the famous Baltic ambers and another that resembles the Agathis group. Fossil resins from the Americas and Africa are closely related to the modern genus Hymenaea. (Lambert JB and Poinar GO Jr. (2002). “Amber: the organic gemstone.” Acc Chem Res. 35(8):628-36.)
The abnormal development of resin has been called succinosis. Impurities are quite often present, especially when the resin dropped on to the ground, so that the material may be useless except for varnish-making, whence the impure amber is called firniss. Enclosures of pyrites may give a bluish color to amber. The so-called black amber is only a kind of jet. Bony amber owes its cloudy opacity to minute bubbles in the interior of the resin.
Inclusions in darkly clouded and even opaque amber inclusions can be imaged using high-energy, high-contrast, high-resolution x-rays.
Extraction and processing
Distribution and mining
Amber is globally distributed, mainly in rocks of Cretaceous age or younger. Historically, the coast around Königsberg in Prussia was the world’s leading source of amber; about 90% of the world’s extractable amber is still located in the Kaliningrad Oblast of Russia on the Baltic Sea. Pieces of amber torn from the seafloor are cast up by the waves, and collected by hand, dredging or diving. Elsewhere, amber is mined, both in open works and underground galleries. The nodules from the blue earth have to be freed from matrix and divested of their opaque crust, which can be done in revolving barrels containing sand and water. Erosion removes this crust from sea-worn amber.
Dominican amber, especially Dominican blue amber, is mined through bell pitting, which is dangerous due to the risk of the tunnel collapse.
The Vienna amber factories, which use pale amber to manufacture pipes and other smoking tools, turn it on a lathe and polish it with whitening and water or with rotten stone and oil. The final lustre is given by friction with flannel.
When gradually heated in an oil-bath, amber becomes soft and flexible. Two pieces of amber may be united by smearing the surfaces with linseed oil, heating them, and then pressing them together while hot. Cloudy amber may be clarified in an oil-bath, as the oil fills the numerous pores to which the turbidity is due. Small fragments, formerly thrown away or used only for varnish, are now used on a large scale in the formation of “amberoid” or “pressed amber”. The pieces are carefully heated with exclusion of air and then compressed into a uniform mass by intense hydraulic pressure; the softened amber being forced through holes in a metal plate. The product is extensively used for the production of cheap jewelry and articles for smoking. This pressed amber yields brilliant interference colors in polarized light. Amber has often been imitated by other resins like copal and kauri, as well as by celluloid and even glass. Baltic amber is sometimes colored artificially, but also called “true amber”.
Often amber (particularly with insect inclusions) is counterfeited using a plastic resin. A simple test consists of touching the object with a heated pin and determining if the resultant odor is of wood resin. If not, the object is counterfeit, although a positive test may not be conclusive owing to a thin coat of real resin. Generally counterfeits will have a too-perfect pose and position of the trapped insect.
Amber occurs in a range of different colors. As well as the usual yellow-orange-brown that is associated with the color “amber”, amber itself can range from a whitish color through a pale lemon yellow, to brown and almost black. Other more uncommon colors include red amber (sometimes known as “cherry amber”), green amber, and even blue amber, which is rare and highly sought after.
Much of the most highly-prized amber is transparent, in contrast to the very common cloudy amber and opaque amber. Opaque amber contains numerous minute bubbles. This kind of amber is known as “bony amber”.
Although all Dominican amber is fluorescent, the rarest Dominican amber is blue amber. It turns blue in natural sunlight and any other partially or wholly ultraviolet light source. In long-wave UV light it has a very strong reflection, almost white. Only about 100 kg is found per year, which makes it valuable and expensive.
Sometimes amber retains the form of drops and stalactites, just as it exuded from the ducts and receptacles of the injured trees. It is thought that, in addition to exuding onto the surface of the tree, amber resin also originally flowed into hollow cavities or cracks within trees, thereby leading to the development of large lumps of amber of irregular form.