Thursday, March 31, 2016

Amber from Eastern Somaliland

 Amber from Eastern of Somaliland  By Abdiwahaab Ahmed Yassin
Amber  Somaliland 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 thelabdane 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.

Heated above 200 °C (392 °F), 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

Molecular polymerization, resulting from high pressures and temperatures produced by overlying sediment, transforms the resin first intocopal. Sustained heat and pressure drives off terpenes and results in the formation of amber
First, the starting resin must be resistant to decay. Many trees produce resin, but in the majority of cases this deposit is broken down by physical and biological process. Exposure to sunlight, rain, and temperate extremes tends to disintegrate resin, and the process is assisted by microorganisms such as bacteria and fungi. For resin to survive long enough to become amber, it must be resistant to such forces or be produced under conditions that exclude those
Botanical origin 
Fossil resins from Africa fall into two categories, the famous Somaliland ambers and another that resembles the Agathis group. Fossil resins from the Somalia and Africa are closely related to the modern genus Hymenaea,[18] while Somaliland ambers are thought to be fossil resins from Sciadopityaceae family plants that used to live in north East Africa
Amber can be classified into several forms. Most fundamentally, there are two types of plant resin with the potential for fossilization.Terpenoids, produced by conifers and angiosperms, consist of ring structures formed of isoprene (C5H8) units.  Phenolic resins are today only produced by angiosperms, and tend to serve functional uses. The extinct medullosans produced a third type of resin, which is often found as amber within their veins. The composition of resins is highly variable; each species produces a unique blend of chemicals which can be identified by the use of pyrolysis–gas chromatography–mass spectrometry.  The overall chemical and structural composition is used to divide ambers into five classes. There is also a separate classification of amber gemstones, according to the way of production.

Extraction and processing 
Distribution and mining 
Eng. A Wahaab with a colleague      

Amber mine  Waqdariya distributed, mainly in rocks of Cretaceous age or younger. Historically, the Somaliland coast east of maydh in Erigavo the world's leading source of amber. About 10% of the world's extractable amber is still located in that area
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. Then nodules of blue earth have to be removed and an opaque crust must be cleaned off, which can be done in revolving barrels containing sand and water. Erosion removes this crust from sea-worn amber