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Amber (fossil resin)
Chemical formula: C10H16O
(succinite), bears succinic acid (3-8%), common fossil remnants of flora and
fauna (mostly insects).
Colour: from almost colourless through yellow, red, brown, bluish to
black (rare). Most common are yellow and orange ("amber") colours
of various saturation, what depends on th admixture of the organic
pigments.
Hardness: 2 - 3 according to the Mohs's scale, sometimes as low as
1,5. Brittleness varies significantly. The values of the absolute hardness
varies for succinite from 17.66 to 38.40 kg per sq mm, for the
"bone" amber 20 kg per sq mm, for "bastard" amber 25 kg
per sq mm, for Carpathian amber 26 kg per sq mm. Melting temperature of
succinite is 340 to 360°C.
Density: 1.07 +/- 0.2; plastic.
Cleavage: absent.
Transparency: from transparent to opaque.
Shine: glassy, resinous, fatty.
Refractive indice: n = 1.540
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| Amber, lump 7.5 cm
long, Kaliningrad region. |
Amber with an
embedded insect 30 mm long, Kaliningrad region. |
Amber is known to the mankind since long time.
Archaeologists found amulets, beads and plates from raw amber in
Palaeolithic graves. Amber was especially sought after in ancient Rome.
One made from it brooches, necklaces, toys in shape of various animals,
human figures. In Western Europe the level of handcraft of amber was
remarkable in 18th century. That time the famous Amber
Room was built - an outstanding masterpiece of Gottfried Gusso [sic! -
Tureau? Goffin Tousseau?]. In 1717 the King of Prussia, Friedrich Wilhelm the 1st presented
the Amber Room to Peter the 1st [tsar of Russia], and several tens of
years later V.V. Rastrelli [Bartolomeo Francesco Rastrelli]
assembled it and reconstructed in the Catherine Palace of the former
Tsarskoye Selo. During the World War II the Amber Room was took away by
Germans. Its further vicissitudes is unknown. [Note: this brief history of
the Amber Room bears many inexact informations, A.K.]
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Primary and secondary
(placer) deposits of amber are distinguished. The type of the
near-shore marine placers has the essential commercial importance.
The fossil resins in nature are found as lumps of various size and
shape. Two their types are distinguished: surficial (80-85%) and
formed inside the tree trunk, under the bark. The largest size (up
to several kilogram) is typical for round lumps, length of the
icicle-shaped forms achieves 15-19 cm, the drop-shaped ones 0.3-4
cm. The shapes caused by transport and abrasion are common - they
ate rounded or oval, the weight of such lumps may reach 6-9 kg (as
found in the Kaliningrad region). Amber lumps are comercially
divided into three classes: for hand crafting, pressed and varnish
type.The first type is clear, in large lumps, sometimes
transparent with inclusions of insects or plants. Pressed amber is
prepared from small grains and tailings from working of the 1st
class amber - it is a good raw material for jewellery as well. It
is prepared by grinding, pressing at low temperature and
subsequent heating to 220-230°C under pressure of 2500 kPa. |
| Industrial open pit
exploitation of amber in the Kaliningrad region; photo taken in
late 1970s. |
The best varieties of the pressed amber are not discernible
from the natural opaque amber and are used for jewellery production. Varnish
amber is used as chemical raw material.
The Baltic amber is the most valuable jewellery raw material of all the
fossil resins; it is called succinite. The following varieties are
distinguished on the basis of its colour and transparency: transparent of
various colour shades, yellow and colourless; smoky,slightly nebulous with
transparent parts; bastard - wax-yellow translucent; bone type - of the
ivory colour; foamy - light, opaque, microporous. The latter is most plastic
(with low brittleness) and very decorative. Succinite, like other fossil
resins - birmite, rumenite simetite, chemavinite, melts very easily, it is
good for turning, drilling and polishing. Sometimes it is improved - boiled
in vegetable oil and coloured with a pigment dissolved in the oil.
Soviet Union gave about 2/3 world production of amber, exploitation and
working is performed in the Kaliningrad region, where at the Primorskoe
deposit there is an open pit mine of amber. Small amber production comes
from Lithuania and Latvia.
Limited amounts of amber are obtained from occurrences in Ukraine,
Belorussia, Arctic regions of Russia, Sakhalin and few other places.
Formation of the near-shore placers
with amber
Since long time there were
numerous findings of the amber-type fossil resins brought by waves
on the beaches of Baltic, White, Barents and Karskoe seas. The
data exist on the ezploitation and handcrafting of amber in the
Arctic sea shores, including the region between the mouths of
Yenisey and Khatanga Rivers. The amber stratiform deposits with
remnants of the ancient soils and redeposited amber accumulations
have been found.
Amber-bearing formation comprises the deposits of the fossil
resins of the biogenioc-sedimentary (promary) and placer
(secondary) deposits. Originally amber occurred in ancient soils,
where the resin of pines and cypresses underwent the diagenetic
processes. |
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| Natural lumps of the
Baltic amber. |
Areas of the Tertiary forests occurred in the Baltic area,
Ukraine, northern Siberia and Far East. Due to erosion the ancient soils
with amber were removed and amber redeposited to the coastal zones by
rivers. Primary deposits are continental sandy-clayey formations with
plant remnants in soils of the ancient forests. They formed from Early
Cretaceous to Quaternary, and occur mainly in northern Siberia and Far
East. Amber is common in the deposits of the Khatanga depression, where
among the pale-gray bedded sands with coal-type material bear reddish ir
yellow amber grains 1-1.5 cm in dia. Thickness of the amber-bearing beds
is about 10 cm. In the shore of Karskoe Sea on the Peschanaya River, 25 km
from the settlement Amderma between sandy-clayey sediments a layer rich in
organic substance occurs; thickness of the amber-bearing bed achieves 0.8
m. Main part of amber occurs as coarse material. The areas of amber
occurrence frequently are connected with the coal-bearing basins,
especially with their periphery zones. N. P. Yushkin defined the following
areas of the fossil resins in the Arctic region: Pechora-Anadyr, Eastern
Urals, Karsk, Indygirka and Penzha-Anadyr. They all bear mostly heavy and
brittle fossil resins, the varieties appropriate for jewellery are
subordinate. Usually improvement of the amber from these areas is
necessary.
Amber from the primary deposits is essentially used in chemical industry
for production of the succinic acid, amber oil, amber varnishes and other
products. For jewellery this amber is less suitable.
Secondary deposits of amber (the lagoon-deltaic marine placers) are the
main source of the high-quality amber raw material for jewellery.
In the Baltic Sea shore, in the Kaliningrad region there is the famous
deposit of the high-quality amber. The total surface of the amber-bearing
beds in this area equals ca. 300 sq. km. The deposit is connected with
Paleogene sandy-clayey rocks, with a transgressive amber-bearing level of
so-called "blue earth", overlain by brown coal Miocene formation
37 m thick, and glacial sediments (18-25 m) occurring on the erosional
surface of the Miocene beds. Ancient rivers transported grains and
lumps of amber to the shallow-water pools, accumulating it in the parts ow
stagnating water, the shelf zone inclusively. Amber occurs as sand size
grains to lumps weighing ca. 10 kg. Almost 75% of the exploited amber has
the size over 1 cm. The highest content of amber occurs in the main
commercial bed - "blue earth", where its coarse lumps are most
common as well. The following varieties of the exploitad amber are
distinguished: transparent, smoky, bastard, bone and foamy
Amber has been gathered in the sea shore since ancient times. In the 17th
century the deposit was exploited by underground shafts and galleries, and
afterwards by the open pit method, currently with use of excavators and
hydraulic method. The rock of the amber-bearin bed is taken to the plant,
where amber is washed out and selected.
Occurrences of the buried amber placers are known in Ukraine, Belorussia,
and other parts of the USSR. In Ukraine amber occassionally has been found
in the Palaeogene deposits; it has red or red-brown colour and unlike the
baltic amber - a brown crust. Numerous findings of amber in Ukraine suggest
their local origin and, in part, transport from the Baltic area by the
continental glacier. In some regions of Ukraine the local amber was used to
production of necklaces and other jewellery. |
