A Background to Horn

A BACKGROUND TO HORN

Horn comes from a group of animals called bovids (family Bovidae), which is a large group of cloven-hoofed mammals encompassing cattle, sheep, goats, antelopes, buffalo and others. Rhinocerous horn is a separate and unique horn, and the rhino is not a bovid. It is the only type of horn which is solid for its entire length, and it also differs in growth and structure. (See ‘A Background to Rhino Horn’)

Horns from various animals: ox, yak, kudu, cow, ram and musk ox.

Bovids carry a pair of horns, which protrude from the front of the skull of the animal. They consist of a sheath of keratin covering a bony core. Horns should not be confused with antlers (the bony, branched structures carried by animals of the Cervidae family, i.e. all types of deer), which are shed annually. Horns are not branched, and they are permanent and grow throughout the animal’s life. Both males and females carry horns, though in a few species only the males do so.

Left: animal skull with one horn sheath cut away to show the bony

protuberance beneath, and right: young water buffalo.

Horn is made mainly of a hard, insoluble protein containing large amounts of sulphur-rich amino acids, called keratin. It occurs widely in the animal kingdom as a constituent of hair and fur, feathers, nails, claws, and skin. Other animal materials such as tortoiseshell, armadillo and pangolin scales are also made predominantly of keratin.

A characteristic of keratin is that it is thermoplastic, which means that it can be heated and re-shaped, retaining its new shape when it cools down. This process can be repeated. Further, horn pieces can be welded together using heat and pressure to make it into larger sheets or to attach it to another, similar, thermoplastic material – e.g. tortoiseshell – to give it bulk. Horn’s thermoplasticity has made it a useful material for many hundreds of years. Another characteristic of horn is that it is water-proof and air-tight. This, and the fact that they are hollow, made horn very suitable for use as snuff boxes or powder horns, where it was imperative that the snuff or gunpowder be kept in the correct conditi

Left to right: horn snuff mull; 2 horn beakers; and cane with ram's horn handle plus unworked ram's horn.

The tip of a horn is not hollow, and can be carved in relief – a process less suitable for the hollow part of a horn where only very shallow carving can be carried out.

Although historically any horn-bearing animal’s horns have been used, some are more suitable than others. Those of cattle are smoother and less intricate in shape, and require less preparation before working. An animal such as the impala has ridged horns which need to be smoothed and flattened before they could be made into items such as drinking vessels. On the other hand, in some cases the shape of the horn was used to advantage. An example of this is snuff mulls where the curve and size of the horn added to the decorative effect, or the curve of a ram’s horn which is a favourite horn of the stick dresser (the carver of cane and stick handles).

The origin of the horn used today for working varies from country to country, most countries availing themselves of local material. In the Far East the most widely used horn is from water buffalo. This is a relatively soft horn to work, and is uniform in colour. In some countries, for example the United Kingdom, most cattle are de-horned in order to prevent injury in the herd, so there is little domestic horn available and the bulk of horn items made are from ox horn (Bos indicus), imported from Nigeria.

IDENTIFYING HORN

Horn-bearing animals are found world-wide, and horns come in a huge variety of shapes and sizes, and in colours ranging from almost white through browns to almost black (see first illustration). Horns can be monochrome or a mixture of these colours. The material has a structure of laminated layers which appears as longitudinal striations. In cross section there may be some vague indication of growth rings, but the solid tips display a pattern looking not unlike fur. In some horn the structure may be easily visible to the naked eye, but -- especially if it is dark in colour -- it may be necessary to examine it under magnification and in strong light.

Left: detail of horn (magnified), showing striations;, and right: cross section

of ox horn and tip of ox horn sectioned longitudinally.

It should be noted that the structure in horn can be destroyed by processing it. The combination of heat and pressure used when shaping can be sufficient to crush the typical striated pattern and render it virtually impossible to see. Taken to the extreme, horn can be clarified by prolonged soaking in water and pressed into thin sheets which are almost transparent. This material was used in past times in lanterns instead of glass.

Horn is not cold to the touch – a characteristic shared by plastic, which is sometimes used to copy it. However plastic lacks the structural pattern of horn. The colours in plastic tend to occur in patches or swirls, rather than the slightly mottled effect of natural horn, and even when an attempt is made at copying the striations the result is not convincing.

Left to right: cross-section of horn tip (polished); detail plastic button imitating horn; plastic hair clips imitating horn.

Horn has itself been used as a simulant copying materials such as tortoiseshell, which was far more expensive. For this the horn was painted with the pattern of tortoiseshell, but the pattern is only on the surface and does not penetrate the material. Horn was used for mourning jewellery in the early nineteenth century, as it could be pressed into shape instead of carved by hand, and when dyed black was an excellent imitation of the more costly jet. (See 'A Background to Jet'.) Items made in this way are often incorrectly labelled as being made of vulcanite (vulcanised rubber, also known as hard rubber or ebonite) which was another jet simulant. Careful examination may be required. It is usually possible to find an area of an item made of horn – for example at the edge of a pressed piece -- that is not totally opaque, and to see an indication of the striations and layers in its structure. Vulcanite is 100% opaque and has no structure.

TREATMENTS

Horn can be processed and treated in a variety of ways. The most usual treatment is to alter its shape by heat and pressure. With the tip of a horn removed, the hollow part can be cut and the material opened up and flattened in a heated press. Shapes can then be punched out and each shape re-heated and pressed to make a new shape, e.g. a spoon. If pressed in a profiled mould, the softened horn will be embossed with the pattern of the mould. The tips of horn can also be turned on a lathe and polished to make, for example, beads.

Left to right: horn opened and flattened and spoon

blanks punched out; Art Nouveau pendant by Mme

Bonté; polished beads carved from the tips of horns.

Horn is rough in its raw state, but takes a good polish. It can be dyed by boiling it in an alkali solution, which softens the horn allowing the dye to permeate it. Horn can also be bleached till it is translucent by prolonged soaking and boiling in water. One use of the translucent and/or dyed horn was in jewellery of the Art Nouveau period. René Lalique was the undoubted master of the craft, and possibly the first of the Art Nouveau designers to use horn. Among the objects produced by Lalique and his contemporaries were jewelled combs, tiaras, brooches, pendants and hat pins.

Horn can be etched by heat which, applied correctly (nowadays using a laser) turns the surface pale golden. Too much or prolonged heat burns the surface. Another method of producing a golden pattern is by making small cuts on the horn’s surface. This is often used on the decorative water buffalo horns sold in the Far East, illustrated with dragons or fishes. The solid tip of water buffalo horn has been used to imitate the vastly more expensive rhino horn.

Detail of carved water buffalo horn, showing lighter

cut areas.

TESTS

As always with organic materials, the best test is to examine the item very thoroughly and carefully in good light, if necessary under magnification. If there is still doubt, a ‘hot point test’ can be carried out, though care must be taken as the early plastic ‘celluloid’ – sometimes used to copy horn or items that could be thought to be horn -- is highly combustible. Further, the test is destructive and will leave a small mark. (The hot point test involves placing the tip of a red-hot pin against the material, to judge whether it burns or not, and what smell it emits. In the case of horn, the smell is like that of burning hair. In a variation of the test – and a safer method – a small scraping is taken of the material from an unobtrusive spot and is held over a flame in order to make the same judgements. This is, however, also a destructive test.)

It is possible to test horn in a laboratory, using FTIR photospectrometry, but even this test can sometimes fail as horn gives a result showing protein, as does the early plastic, casein, which was often used to copy the same things as horn, or indeed to copy horn itself. (Casein is a semi-synthetic plastic, derived from the curds made from skimmed milk, and formaldehyde.) FTIR can therefore be inconclusive. When the material is dyed to resemble jet it becomes even more confusing as the black colour gives poor results.

CARE OF HORN

Horn is a reasonably durable material in use. It is not affected by salt or vinegar so can be made into salad bowls or servers where it comes into contact with salad dressing. It should be remembered that it is a soft material and can be scratched. It can also be attacked by some insects, such as clothes moths.

The most common cause of damage to horn items is probably heat. As earlier stated, horn is a thermoplastic material, and may change shape and lose its patina if subjected to high temperatures, for example by being washed in a dishwasher.

HORN AND ENDANGERED SPECIES

Although animals such as cows, sheep, water buffalo and bison are plentiful enough, there are several species of bovid that are protected by CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora). Some appear under Appendix II which strictly regulates the trade of the animal or its parts. At present there are over twenty bovids covered by Appendix I which prohibits absolutely any trade in any part of the animal. The protected animals are seldom poached for the beauty of their horns. It is more likely that a part of the animal is collected for use in Oriental medicines.