History

The name comes from the Arabic عنبر, ʻanbar, probably through Spanish, but this word referred originally to ambergris, which is an animal substance quite distinct from yellow amber. True amber has sometimes been called kahroba, a word of Persian derivation signifying "that which attracts straw", in allusion to the power which amber possesses of acquiring an electric charge by friction. This property, first recorded by Thales of Miletus, suggested the word "electricity", from the Greek, elektron, a name applied, however, not only to amber but also to an alloy of gold and silver. By Latin writers amber is variously called electrum, sucinum (succinum), and glaesum or glesum. The Old Hebrew חשמל hashmal seems to have meant amber, although Modern Hebrew uses Arabic-inspired ענבר `inbar. The Polish word is bursztyn; the German word is Bernstein.

Composition

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, communic acid, cummunol and biformene ^[1]. Labdanes are tetrameric terpenes (C₂₀H₃₂) and trienes which means that the organic skeleton has three alkene groups available for polymerization. As amber matures over the years, more polymerization will take place as well as isomerization reactions, crosslinking and cyclization. The average composition of amber leads to the general formula C₁₀H₁₆O.

Amber in Geology

The Baltic amber or succinite (historically documented as Prussian amber) is found as irregular nodules in a marine glauconitic sand, known as blue earth, occurring in the Lower Oligocene strata of Sambia in Kaliningrad Oblast, where it is now systematically mined ^[2]. It appears, however, to have been partly derived from yet earlier Tertiary deposits (Eocene); and it occurs also as a derivative mineral in later formations, such as the drift. Relics of an abundant flora occur as inclusions trapped within the amber while the resin was yet fresh, suggesting relations with the flora of Eastern Asia and the southern part of North America. Heinrich Göppert named the common amber-yielding pine of the Baltic forests Pinites succiniter, but as the wood, according to some authorities, does not seem to differ from that of the existing genus it has been also called Pinius succinifera. It is improbable, however, that the production of amber was limited to a single species; and indeed a large number of conifers belonging to different genera are represented in the amber-flora.

Amber inclusions

Locations and utilization

Although amber is found along the shores of a large part of the Baltic Sea and the North Sea, the great amber-producing country is the promontory of Sambia, now part of Russia. Pieces of amber torn from the sea-floor are cast up by the waves, and collected at ebb-tide. Sometimes the searchers wade into the sea, furnished with nets at the end of long poles, by means of which they drag in the sea-weed containing entangled masses of amber; or they dredge from boats in shallow water and rake up amber from between the boulders. Divers have been employed to collect amber from the deeper waters. Systematic dredging on a large scale was at one time carried on in the Curonian Lagoon by Messrs Stantien and Becker, the great amber merchants of Königsberg. At the present time extensive mining operations are conducted in quest of amber. The pit amber was formerly dug in open works, but is now also worked by 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. The sea-worn amber has lost its crust, but has often acquired a dull rough surface by rolling in sand.

Varieties

Besides succinite, which is the common variety of European amber, the following varieties also occur:

1. ^ Assignment of vibrational spectra of labdatriene derivatives and ambers: A combined experimental and density functional theoretical study Manuel Villanueva-García, Antonio Martínez-Richa, and Juvencio Robles Arkivoc (EJ-1567C) pp 449-458 Online Article
2. ^ Langenheim, Jean (2003). Plant Resins: Chemistry, Evolution, Ecology, and Ethnobotany. Timber Press Inc.. ISBN 0-88192-574-8.

• This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain.