Other Materials

Gold

Unlike other metals, gold usually occurs in its metallic form and needs no smelting, although to free it from other metals, and to increase its purity, it must go through complex refining processes. Gold also occurs as a constituent in alloys, with other metals such as silver, copper and platinum. In the earth, metallic gold is released as dust or nuggets by mechanical forces like crushing and grinding, eventually appearing in surface soils, which may be reburied over time, or washing into streams. The traditional form of extraction in Africa was by panning from such streams. Since the late 19th century, mines have been dug, the deepest going down 4000 metres (13,200 ft). In 1977, nearly 75% of the world's supply of gold was produced in Africa, most prolifically in South Africa (95%) also Zimbabwe (2.26%), Ghana (2.24%) and 12 other African countries.

Gold is both ductile and malleable. One ounce can be stretched into a thread over a mile long or beaten into a sheet over 5 metres(16ft) square. It can be worked cold and does not harden when hammered. Plating, gilding, filigree work and beading have been common methods of decoration. The most widespread way of making gold ornaments in Africa, particularly west Africa, is by means of the lost wax process. In this, a model of the desired form is made in wax (sometimes using other materials such as latex) surrounded in fine clay. The model and mould is heated to melt the wax out, then the mould is refilled with gold; when cool, the baked clay is broken away to reveal a unique cast figure. Jewellery such as finger rings, beads and ornaments usually worn round the neck were made in this way.

With the exception of the Akan-speaking nations of Ghana and Ivory Coast, gold was not a significant element in African belief systems except in relation to its trade value with other communities, mainly outside sub-Saharan Africa . It was incorporated into the Roman monetary system via Carthage and the trans-saharan trade routes, and the Arabic system via the Swahili trade of the east Coast. The name of the earliest European settlement on the west African coast was Elmina, the mine; the over-riding initial interest of Europeans was in the gold trade and wresting control of it from the North African Islamic powers. Later of course, greed over the commercial potential of the trade in people took over.

Gold has been an important trade item for more than 2000 years. The ancient Sudanese kingdom of Meroe acted as a trading centre for the gold produced in the upper Nile in the last centuries BCE. In the early centuries of the Christian Era, Nubian kingdoms, such as Alodia, diverted the trade through their cities. By the 6th century CE the gold was being traded through Aksum to the Red Sea port of Adulis, into Arabia . The earliest signs of gold being a significant factor in trading relations in West Africa was in the old kingdom of Ghana, about 1100 years ago. It controlled the trade in gold from Bambuk as well as those nearer the coast in what were to become the Ashanti goldfields. The metal was available on the East African coast to Swahili traders from the 8th century CE onwards. Coming from the Zimbabwean plateau. It was trade to the Middle East and India. This trade influenced the emergence of chiefship on the plateau and in the Transvaal region. Mapungubwe and later Great Zimbabwe built their power on trade in ivory, copper as well as gold.

White metals: Aluminium, Tin, Zinc, and their alloys

Although aluminium is the most common metal, it cannot be produced without employing industrial-scale processes. It does not occur naturally in metallic form, and extracting it from its ore demands more energy than can be accomplished by smelting. Ghana is a major source and producer of aluminium, but only since the construction of the Volta Dam made large amounts of electricity available to process it. Many everyday utensils produced commercially from aluminium are used throughout Africa; some forms are made by local metal workers using traditional casting methods, possible since the melting point of aluminium is 659°C. Ref: Historical Atlas of Africa, Cambridge Encyclopaedia of Africa.

Tin is found in large quantities in Nigeria, also to a lesser extent in the Democratic Republic of Congo and South Africa. On the Jos Plateau area of central Nigeria, tin was extracted from cassiterite by smelting, and cast into 'straws', used as currency.

Zinc is not produced in great quantities in Africa, only about 5% of world production. It has never been worked indigenously. The source of the zinc in the figures from Cameroon is impossible to establish; the variable amounts in the different figures would suggest that the alloy metals used in casting were scrap pieces, such as printing plates or battery linings or even imported zinc statuary, although the absence of aluminium is difficult to explain. Ref: Conservation of a group of metal figurines from Cameroon.

'White-metal alloy' is as generic term covering alloys with varying proportions of metals such as aluminium, zinc, tin, chromium, lead, nickel, mercury, but not excluding darker metals such as copper, and possibly some silver, but excluding iron in any quantity, because of its effect of raising the melting temperature above what is practical. Much of the African caster's raw material consists of non-ferrous scrap metal from a wide variety of sources, such as old utensils, batteries, bullet cases, car parts. The precise make-up of the alloy is not as important to the caster as the colour and overall appearance of the finished product.

Silver

Little silver has been found in the soils of Africa. Items made of silver are particularly associated with Tuareg groups in Niger and communities in Ethiopia. In both cases, the raw material is Austrian silver thalers or dollars, originally produced to commemorate the reign of Empress Maria Theresa in 1780. They have been in use as currency or a store of wealth in Sudan, Ethiopia, and Nigeria as well as the former French colonies of West Africa since the latter part of the 18th century until at least the 1960s. Jewellery, and in Ethiopia, crosses, were and are made using the lost-wax process, by specialist silver smiths. Where items datable to before the advent of these thalers exist, such as the medieval silver cross of the Ethiopian Christian centre of Lalibela, it is possible to suggest that earlier external sources of silver coinage had been utilised in the same manner.

Wire

Wire is often used to decorate objects. Now it is sold in shops, but formerly was made in a small number of specialist workshops.

Although all the wire used in decorating objects in Africa in recent years has been produced from imported sources of iron, copper and brass, as well as gold and silver, it was formerly made in many parts of Africa. The most important places where it was made were found in Ruanda, and adjacent parts of Tanzania south-west of Lake Victoria, using locally smelted iron and Katanga, the southern region of the Democratic Republic of Congo, using the local sources of copper.