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What is amber?
Amber is fossilised resin and may be clear or opaque (osseous amber), and deep reddish orange to creamy yellow. The amber found in Norfolk is the same as that found in the Baltic and came from pine trees that grew in forests somewhere in Europe in the Oligocene period, about 40 million years ago. Nothing remains of the forest floor and we do not even know where it was but blobs of resin exuded from the trunks were washed down to the sea and preserved in beds of clay on the sea floor. Today these deposits of Oligocene clay containing amber are found on the southern shores of the Baltic Sea, in northern Poland and Russia. Amber was once collected from the shore there after it was eroded from the clay but now it is mined.
Rarely pieces of amber contain inclusions, such as bubbles, pieces of twig and bark and even insects that became trapped and entombed, remaining perfectly preserved.
How did it get to Norfolk?
Baltic amber was probably transported towards Britain during the ice age (in the last few hundred thousand years) by ice sheets moving out of southern Scandinavia and across the North Sea. Today it may be derived by erosion of glacial deposits in the cliffs of Norfolk, or deposits offshore and washed onto our beaches. There appears to have been more amber found in the past than now, perhaps because cliff erosion has been reduced by coast protection works that have been built in the 20th century. In the 19th century several Cromer traders advertised themselves as amber dealers and craftsmen.
Nowadays, a few local people walk the Norfolk beaches regularly and collect small amounts, especially after winter storms have driven the amber ashore. It is said to be found most commonly on the strandline, where the amberweed (Flustra foliacea) gathers but may also be caught amongst the stones on the foreshore.
How can you tell if it is amber?
Amber is not the only orange-coloured stone found on our beaches. There are carnelians, chalcedony, and flints which might be confused with it. Some simple scientific tests will discriminate between them.
Firstly, like plastic, amber is relatively light and soft. Carnelian and flint are both hard and dense. The surface of amber is usually dull like orange peel. It is not usually polished and smooth until it is worked. Amber (and other plastics and resins) can be easily scratched with a knife, so it can be easily worked for jewellery. Flint, chalcedony and carnelian of the other hand cannot be scratched, although the knife may draw a line of grey steel on them.
Amber can float in strong brine, but not sea water. Take half a cupful of hot water and dissolve ten teaspoonfuls of salt in it. Amber will float (it has an average density 1.08) whilst other common minerals from the beach will 'sink like stones'. With experience, pieces of amber will feel much lighter than similar sized stones. Amber will also feel warm to the touch and it will burn. It also generates a static charge when rubbed, but then so do many plastics.
Telling amber from other resins and plastics takes more experience and scientific testing, but amber is more resistant to solution in alcohol than say copal (which is used in traditional varnishes). Amber and copal tend to chip when scratched by a slightly blunt blade, whilst plastic imitations can be pared. Because amber is so old it is stable and over time its surface will not craze like modern resins do. Amber will benefit from handling, due to oils absorbed from the skin and it becomes dull when left in a drawer for years.
Helen Fraquet : 1987 : Amber : Butterworth
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