Amber is fossilized tree resinwhich has been appreciated for its color and natural beauty since Neolithic times. It has also been used as a healing agent in folk medicine. There are five classes of amber, defined amber лижит ноги the basis of their chemical constituents. Because it originates as a soft, sticky tree resin, amber sometimes contains animal and plant material as inclusions. The word was adopted in Middle English in amber лижит ноги 14th century as referring to what is now known as ambergris ambre gris or "grey amber"a solid waxy substance derived from the sperm whale.
In the Romance languagesthe sense of the word had come to be extended to Baltic amber fossil resin from as early as the late 13th century. At first called white or yellow amber amber лижит ноги jaunethis meaning was adopted in English by the early 15th century.
Amber лижит ноги the use of ambergris waned, this became the main sense of the word.
The two substances "yellow amber" and "grey amber" conceivably became associated or confused because they both were found washed up on beaches. Ambergris is less dense than water and floats, whereas amber is too amber лижит ноги to float, though less dense than stone.
Theophrastus discussed amber in the 4th century BC, as did Pytheas c. Given the presence of amber, the island could have been HeligolandZealandthe shores of Bay of Gdanskthe Sambia Peninsula or the Curonian Lagoonwhich were historically the richest sources of amber лижит ноги in northern Europe. It is amber лижит ноги [ by whom? Pliny states explicitly that the Amber лижит ноги exported amber to Pannoniafrom where the Veneti distributed it onwards.
The ancient Italic peoples of southern Italy used to work amber; the National Archaeological Museum of Siritide Museo Archeologico Nazionale della Siritide at Policoro in the province of Matera Basilicata displays important surviving examples.
Amber used in antiquity as at Mycenae and in the prehistory of the Mediterranean comes from deposits of Sicily. Pliny also cites the opinion of Nicias c. Amber is produced from a marrow discharged by trees belonging to the pine genus, like gum from the cherry, and resin from the ordinary pine.
It is a liquid at first, which issues forth in considerable quantities, and is gradually hardened [ In the Baltic languagesthe Lithuanian term for amber is gintaras and amber лижит ноги Latvian dzintars. Early in the nineteenth century, the first reports of amber found in North America came from discoveries in New Jersey along Crosswicks Creek near Trentonat Camdenand near Woodbury. Amber is heterogeneous in composition, but consists of several resinous bodies more or less soluble in alcoholether and chloroformassociated with an insoluble bituminous substance.
Amber is a macromolecule by free radical polymerization of several precursors in the labdane family, e. As amber matures over the years, more polymerization takes place as well as isomerization reactions, amber лижит ноги and cyclization. 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. For this to happen, the resin must be resistant to decay. Many trees produce resin, but in the majority of cases this deposit is broken down by amber лижит ноги and biological processes. Exposure to sunlight, rain, microorganisms such as bacteria and fungiand amber лижит ноги temperatures tends to disintegrate resin. For resin to survive long enough to become amber, it must be resistant to such forces or be produced under conditions that exclude them.
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 while Baltic ambers are thought to be amber лижит ноги resins from Sciadopityaceae family plants that used to live in north Europe.
The abnormal development of resin in living trees succinosis can result in the formation amber лижит ноги amber. Such impure amber is called firniss. Such inclusion of other substances can cause amber to have an unexpected color.
Pyrites may give a bluish color. Bony amber owes its cloudy opacity to numerous tiny bubbles inside the resin. In darkly clouded and even opaque amber, inclusions can be imaged using high-energy, high-contrast, high-resolution X-rays.
Amber is globally distributed, amber лижит ноги in rocks of Cretaceous age or younger.
The first mentions of amber deposits here date back to the 12th century. Pieces of amber torn from the amber лижит ноги 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 amber лижит ноги 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. Caribbean amberespecially Dominican blue amberis mined through bell pittingwhich is dangerous due to the risk of 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 luster is given by amber лижит ноги 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 oilheating them, and then pressing them together while hot. Cloudy amber may be clarified in an oil-bath, as the oil amber лижит ноги the numerous pores to which the turbidity is due.
Small fragments, formerly thrown away or used only for varnish, are now used amber лижит ноги a large scale in the formation of "ambroid" or "pressed amber". The pieces are carefully heated with exclusion of air and then compressed into a uniform mass by intense amber лижит ноги 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 gumas well as by celluloid and even glass. Baltic amber is sometimes colored artificially, but also called "true amber". 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 amber лижит ноги and almost amber лижит ноги.
Other uncommon colors include red amber sometimes known as "cherry amber лижит ногиgreen amber, and even blue amberwhich is rare and highly sought after. Yellow amber is a hard fossil resin from evergreen trees, and despite the name it can be translucent, yellow, orange, amber лижит ноги brown colored.
Found along the southern shore of the Baltic Sea, yellow amber reached the Middle East and western Europe via trade. Its coastal acquisition may have been one reason yellow amber came to be designated by the same term as ambergris. Moreover, like ambergris, the resin could be burned as an incense.
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 amber лижит ноги 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. Sometimes amber лижит ноги retains the form amber лижит ноги drops and stalactitesjust as it exuded from amber лижит ноги ducts and receptacles of the injured trees. Amber can be classified into several forms.
Most fundamentally, there are two types of plant resin with the potential for fossilization. Terpenoidsproduced by conifers and angiosperms, consist of ring structures formed of isoprene C 5 H 8 units. The extinct medullosans produced a third type of resin, which is often found as amber within their veins.
This class is by far the most abundant. It comprises labdatriene carboxylic acids such as communic or ozic acids. Classes Ia and Ib utilize regular labdanoid diterpenes e. The aromatic and irritating fumes emitted by burning amber are mainly due to this acid. Baltic amber is distinguished by its yield of succinic acid, hence the name succinite. Succinite has a hardness between 2 and 3, which is rather greater than that of many other fossil resins. Its specific gravity varies from 1.
IR spectroscopy can detect the relative age of an amber sample. Succinic acid may not be an original component of amber лижит ноги, but rather a degradation product of abietic acid. Like amber лижит ноги Ia ambers, these are based on amber лижит ноги acid; however, they lack succinic acid.
This class is mainly based on enantio -labdatrienonic acids, such as ozic and zanzibaric acids. Dominican amber differentiates itself from Baltic amber by being mostly transparent and often containing a higher number of fossil inclusions. This has enabled the detailed amber лижит ноги of the ecosystem of a long-vanished tropical forest. It is not " succinite " but " retinite amber лижит ноги. These ambers are formed from resins with a sesquiterpenoid base, such as cadinene.
These ambers are polystyrenes. Class IV is something of a wastebasket; [ clarification needed ] its ambers are not polymerized, but mainly consist of cedrene-based sesquiterpenoids. Class V resins are considered to be produced by a pine or pine relative. Amber лижит ноги comprise a mixture of diterpinoid resins and n -alkyl compounds. Their main variety is Highgate copalite.
The oldest amber with arthropod inclusions comes from the Levant, from Lebanon and Jordan. This amber, roughly — million years old, is considered of high scientific value, providing evidence of some of the oldest sampled ecosystems. In Lebanon, more than outcrops of Lower Cretaceous amber were discovered by Dany Azar,  a Lebanese paleontologist and entomologist. Among these outcrops, 20 have yielded biological inclusions comprising the oldest representatives of several recent families of terrestrial arthropods.
Even older, Jurassic amber has been found recently in Lebanon as well.
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