Jewelry Lovers

Coral

Like a pearl, coral is formed by an animal separating calcium carbonate from seawater and re-depositing it. In the case of coral this is done by the coral polyp, a primitive plant-like animal which spends its life attached to the coral which its ancestors produced. Millions of certain types of these animals together produce whole reefs of coral, the most famous of which is the Great Barrier Reef off Australia. It is, however, not this reef-building coral which is used for jewellery but a tree-like type called Corallium nobile, which exists in a number of areas but notably in the Mediterranean and on the coasts around Malaysia and Japan. The existence of coral around the Italian coastline led to the setting up of a coral- cutting industry at Torre del Grecco near Naples. Even now, when Italian sources are all but worked out, the workers of Torre del Grecco continue to produce beads and small carvings with primitive hand tools from imported coral.

Coral is very soft, at 31 on Mohs’ scale, and must be carefully handled because it is easily broken. It is found in a variety of colours - white, different shades of pink, and various reds. Even black coral is sometimes found. Some people prefer one shade and others another, but the pale pink called by the Italians pelle d’angelo, or angel’s skin, and the rich red called rosso, are perhaps the most sought after.

Nowadays a lot of coral is ‘improved’ by staining. Rubbing the coral with a cloth damped with a drop of nail varnish remover will usually detect the presence of stain. Many imitation corals have been produced from glass, porcelain and plastic. A simple test is to drop a little bland acid (such as vinegar) carefully on to the coral. If it is genuine the acid will cause the calcium carbonate of which the coral is composed to effervesce.

Amber

This beautiful waxy substance, the colour of honey, originally came from trees. It is a resin exuded by a prehistoric pine tree of a type that no longer exists. It hardened with time and sometimes, as it ran down those trees 30 million years ago, tiny insects or bits of vegetation got caught in it and were entombed there for ever. There is a collection of amber in a museum in Kaliningrad in the US SR where 50,000 specimens of creatures and plant fragments are to be seen in the amber taken from nearby deposits. The area around Kaliningrad on the Baltic has been the traditional source of amber for centuries, but amber has also been found elsewhere - in Burma for instance. It can be picked up along the east coast of England, having been carried by the sea from the Baltic shores. Amber is found in various shades from yellow to reddish brown and is very soft.

Glass and plastic imitations of amber exist, and small fragments of the material can be heated and pressed together to produce a material sometimes called ambroid. An expert can easily spot pressed amber, and in fact anyone can learn to spot the differences in clarity at the margins between the pieces. Pressed amber is acceptable, provided you are not being asked to pay the price of untreated material. It is possible to test amber by cutting off a fragment with a knife blade and burning it. Amber responds to the blade quite differently from glass or plastics, and gives off an aromatic smell when burnt. The fact that there is a fly entrapped in the material does not guarantee that it is amber - plastic imitations complete with flies have been produced in their thousands.

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