Ivory: the ancient treasure

Many people associate ivory with elephants but it is also prevalent in the tusks of the hippopotamus, walrus, warthog, sperm whale and orca species. Examples of tooth ivory, however, are less common and generally limited to hippopotamus and sperm whale teeth. 

The African elephant produces the greatest amount of commercial ivory. Each elephant's tusks weigh an average of seven kilograms and can grow to 3.5 metres long.  

Because they are hunted specifically for this purpose, African elephant numbers are dwindling and the beast is in danger of extinction. Since 1991, there has been a world export ban on ivory, however, poaching still continues. 

Almost all of ivory – some 95 per cent – is a chemical substance known as dentine. This hard, opaque material is valued most when it exhibits a warm tint with little grain or mottling.  

Ivory has historically been used as a medium for artworks. Early species of man were thought to be the first to carve in ivory (mammoth tusks). Perhaps the earliest examples are crude carvings found on mammoth ivory in caves in Périgord, France and again in some Swiss lake dwellings. 

Both the Greek and Roman civilizations used large quantities of ivory to sculpt religious objects and decorative boxes. A small ivory head was uncovered at Vestonie and estimated to be 30,000 years old. The gold-encrusted Snake Goddess of Knossos or treasures of Tutankhamun's tomb are also ivory pieces. 

In modern times, ivory remains a most prestigious material for carving. Because it's so soft - rating between 2.25 to 2.75 on Moh's scale - tooth and tusk ivory can be modelled into an endless variety of shapes and objects. Billiard balls, piano keys and buttons were fashioned from ivory prior to the introduction of plastic. 

Over the last 200 years, ivory has been a favourite material for East Asian jewellery, traditional art and ethnic crafts also. Today there is a trend toward carving or scrimshawing warthog tusks and teeth from sperm whales, orcas and hippopotami to retain their natural shape. 

   

Fossil ivory is obtained from the remains of the woolly mammoth, extinct since the Ice Age some 10,000 years ago. Though some of these tusks have lost aesthetic quality over time, many were well preserved beneath the ice. Most of these fossilised tusks have been found in Siberia, particularly around rivers that run into the Arctic Ocean such as the Lena River. Trade in the ivory from the tusks of dead mammoths has occurred for 300 years and continues to be legal. 

As a soft, organic gem, ivory requires special care and gentle cleaning. Once any polish has worn away, the gem reveals an absorbent nature. When fatty acids and oil imparted from the skin come into contact with ivory, it will yellow somewhat. Ivory should be occasionally wiped with methylated spirits to remove this grime. 

Stains from perfume and other toiletries are much harder to remove and wearers should attempt to protect ivory from contact with these substances. Prolonged exposure to high temperatures should also be avoided. Conversely, ivory can be bleached under excessive exposure to sunlight.