A BACKGROUND TO IVORIES
An introduction to ivories, covering different types, their simulants and their fakes, how to recognise and test them, and trade bans.
Ivory comes from the teeth or tusks of a mammal. Tusks are also teeth, but they are larger and protrude from the mouth. Ivories have been put to both decorative and utilitarian uses for thousands of years. The most famous ivory comes from the tusks of elephants, both Asian and African (both the males and females bear tusks in Africa, but only the male Asian elephants carry them). Historically, ivory has also come from walruses, hippopotamuses, various whales, members of the pig or suid family, and the remains of mammoths.
The purpose of an animal's teeth is obvious - they are for tearing or grinding up food whilst eating. The purpose of tusks is less obvious, and each animal has developed these oversized teeth for different reasons. Elephants use theirs to strip bark (their food) from trees. Walruses use theirs to pull themselves up onto ice floes, and to trawl the sea bed. Many animals use their tusks for display (especially in the mating season), and for fighting.
WHAT IS IVORY?
Teeth consist mostly of dentine, a creamy-white, opaque material made up mainly of calcium phosphate, with some collagen. The dentine is covered in enamel which is very hard, and is often worn away by the animal through foraging and eating. Any enamel remaining on the tooth or tusk is usually removed before the material is carved. Cementum may also partially cover the dentine, and it holds the teeth or tusks in place in the animal’s jaw. Dentine, enamel and cementum all have a very similar colour.
The tusks of elephants, mammoths, walruses, hippos and whales are solid for much of their length. Those from the male narwhal (a small, arctic whale which usually carries a single, spiralling tusk that can measure up to 2m in length), are hollow, and tusks from some of the suids, e.g. wild boar or warthog, may be hollow for much of their length.
RECOGNISING THE VARIOUS WORKED IVORIES
When worked, ivory has a high polish and a silky feel. The different ivories have characteristics that can enable us to recognise from which species they are derived. For example, when cut in cross section, elephant ivory displays a pattern of intersecting arcs commonly called the ‘engine turning’ pattern (and sometimes incorrectly called ‘lines of Retzius’). Viewed along its length, it has irregular, wavy lines.
Fossilised mammoth (left) and walrus ivories (right) showing diagnostic structure. Both ivories have become stained through age.
Walrus ivory was used a lot in Europe in the Middle Ages as it was not possible to obtain elephant ivory. Also solid, it is the only ivory to have two distinct types of dentine, the outer displaying very fine concentric rings, and the inner a material that is best described as resembling milky rice pudding. This secondary dentine is as hard as the primary, and can be carved in the same way. It is sometimes possible to find fossilised walrus ivory, and though it tends to be rather stained, it has the same characteristic structure as new walrus ivory.
Narwhal ivory is often recognised by the fact that it is hollow and could therefore not be carved into solid figures. It was instead used in sections or small pieces, and sometimes whole as in walking canes or bishops’ crosiers. The outer surface of the ivory retains a diagonal pattern, even after polishing, caused by the spiral growth pattern. This material has been used predominantly in countries with access to, or trade around, the arctic seas.
Sperm whale teeth, and those from the orca (also known as the killer whale), are much smaller and peg-shaped. They are solid but have a fine, dark line running down the centre of the tooth, which sometimes shows in a carving. They also have a distinct line between the dentine and the cementum, which covers the tooth.
Sperm whale tupilak carving from Greenland, showing central dark line and dentine/cementum demarcation.
The tusks of animals in the pig families vary in size according to the species, but most are not very large, and many are hollow. They are a triangular shape in cross-section, curved, and are not usually suitable for carving but are sometimes used whole, with smaller examples strung together as bracelets. When encountered whole, the larger more solid tusks from these animals can be confused with the lower canine teeth of the hippo which are also solid and curved, but which have a flattened, worn area at the tip where the tooth has rubbed against teeth in the upper jaw. Hippo ivory lacks distinguishing structural patterns, is very dense and is stain resistant.
Mammoth ivory resembles elephant ivory very closely. It is found in the permafrost in the northern hemisphere, and is 10,000 or more years old. Due to its age it is often cracked, and sometimes stained a brown colour. As some has been deep-frozen rather than fossilised, it can also occur as a very pale material and in good condition. In pieces and carvings that are large enough to show a section of the ‘engine turning’ pattern, it may be possible to detect that the intersecting arcs have a more acute angle than those of elephant ivory. This is most easily visible at the outer edge of the dentine.
IVORY& BONE, AND OTHER LOOKALIKES
The material most commonly confused with ivory is bone. It has the same colour and in small pieces it may not be possible to discern any structure. However, almost all bone is hollow and cannot therefore be carved into solid figures. To construct an item from bone with a top and bottom (e.g. the box illustrated), there must be joins. Also, bone has a characteristic totally lacking in ivories: tiny, nutrient-bearing canals, called Haversian canals. These appear as dark dots in cross-section, and as little lines along the length of the material.
Antler is a form of bone (and is a completely different material to horn). It also has Haversian canals, but it is often darker than bone, and it has a hard, finely-honeycombed centre. Only when this is cut away is it difficult to tell bone and antler apart.
Plastic is a popular imitation for ivory, but, unless a heavy filler has been added in manufacture, it lacks the weight and feel of the natural material. Early plastics used to imitate ivory were given various names such as Gallalith and Ivorine. Some of the imitations had no structural characteristics at all, whilst others imitated the engine turning pattern. In cross-section they appear as alternating dark and light areas rather than as intersecting arcs, and in longitudinal section they display parallel lines, rather than the irregular wavy ones of elephant ivory.
Other fakes have been made from powdered, re-constituted bone. Although the weight and colour may be more convincing, there is a lack of structure in this material. Further, any material that has been constructed and moulded may show tell-tale signs, such as air bubbles or marks from the joins in the moulds.
TESTS FOR IVORY
It can be almost impossible to tell exactly which type of ivory has been used to make an object. It is more important to know whether it is ivory or bone – materials which have, as already mentioned, certain characteristics, though these may be difficult to see in very small pieces, finely carved items, or furniture inlay.
A test that is sometimes carried out in a gem testing laboratory is to place the item under ultraviolet light to see whether it fluoresces. However, this test will not differentiate ivory from bone, as both fluoresce with a chalky white colour. Casein, an early plastic that was used to imitate ivory, also fluoresces in the same way. There are other, advanced tests using expensive equipment that can determine which species the ivory comes from. But in general, everyday practice, by far the best way to identify ivory is by sight. Careful and thorough examination, viewing all parts of the article from various angles in good light, will usually reveal what it is.
WHERE TO SEE IVORIES
Ivory has been carved by mankind for over 20,000 years, though very few ancient pieces survive as ivory is less durable than, for example, gem minerals.
There are beautiful collections of ivories in many museums, world-wide, from the almost 3000 year old Assyrian ivory panels on show in New York, London and Bagdad, through the collections of medieval ivories in many European museums, to the later items such as dressing table sets of ivory-backed brushes which were popular in the twentieth century. Collections of Inuit artefacts always include arctic ivories used as talismans, decoration, or utilitarian objects such as harpoon tips. Whaling museums on both sides of the Atlantic have collections of scrimshaw, which are items made from materials (including ivory) that have been derived from whales, and carved, etched and decorated.
TRADE BANS
Ivory has been so widely used that many of the animals from which it derives are now under serious threat of extinction. This is especially true of the elephant which was killed purely for its tusks. The slaughter was widespread with the result that, for example, African elephant numbers plummeted from an estimated 1.3 million animals in 1979 to just over 600,000 ten years later. Although whales are also under threat, their ivory has been a bi-product rather than the reason for their slaughter. As a result of the threat of extinction, there are now very strict ivory trade bans in operation.
There are exceptions to the bans, such as mammoth and fossilised walrus ivory, and any ivory items that can be documented to pre-date June 1947. In some countries such as South Africa it is legal to carve and sell ivory –including elephant ivory -- from animals culled in Kruger National Park, but only for domestic consumption. To export them without a government permit would be in contravention of the law.
The Inuit are allowed to catch an annual quota of their local animals, including arctic whales, and to carve and sell the ivory derived from them. This is regulated and carried out under strict licence, and, again, the resulting items cannot be freely imported into most countries, though single items for personal use may be allowed with the appropriate documentation.
Three African countries (South Africa, Namibia and Botswana) are at present endeavouring to fulfil terms and regulations to allow them a one-off sale to either China and/or Japan of their huge stockpile of elephant ivory tusks, which they have not been allowed to trade since the bans came into effect in 1989. These terms include proving that poaching is under control in their country. Conservation and Animal Welfare groups are opposed to this decision as any legal trade in ivory could create a smokescreen for illegal trade. It is not possible to identify raw ivory and thus prove its provenance without extremely expensive testing (which would have to be carried out on each piece).
In some Far Eastern countries illegal new elephant ivory can be seen for sale alongside mammoth ivory --which is sold legally as the mammoth is already extinct -- and it can be difficult to tell the two types apart. Also, ivory can be ‘aged’ by soaking it in a liquid such as tea or tobacco juice to stain it and give it an antique look. But even genuine age is not a guarantee that the material can be traded. For example, in the United Kingdom it is illegal to re-work old ivory for commercial use. It must have been worked pre- June 1947 to be sold. In the United States the law varies with each state.
Anyone wishing to purchase ivory is advised to bear these facts in mind. Further information can be obtained from the appropriate authorities and from conservation groups, and items should only be bought from reputable dealers who can provide the correct documentation. If attempting to export or import ivories of any type, documentation needed will include proof of provenance, CITES (Convention on International Trade in Endangered Species) certificates, and export and import licences. These can take several weeks to obtain.
(The author is indebted to IFAW -– the International Fund for Animal Welfare – for information concerning trade bans).
Note: This article has previously been freely accessible and therefore continues to appear if 'Googled'. It is part of the organic gem materials archive called 'Organic Gems'. See www.maggiecp,com for more articles and information.
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