Zimbabwe is the only African country where there is significant sculpting in stone. Elsewhere wood carving is the preferred form of artistic expression.

This is original, fine art created entirely by hand. No power tools of any kind are used.

Each sculpture exhibited is created out of a single piece of stone. The astonishing range of colour and texture in the sculpture – creating the impression sometimes of different stones that are joined together – is achieved by using different carving techniques, leaving parts of the stone unworked, and by polishing other parts.

Many of sculptors rely on hand-made tools, using bits of scrap iron, because they can afford nothing better – although the African Millennium Foundation's New-for-Old project to replace roughly hewn hand-made tools with efficient, modern, custom-made sculpting tools is slowly changing this.

To polish the stone the entire sculpture is first heated by direct immersion in a fire, or by building a fire in an oil drum and wheeling the sculpture around it to distribute the heat evenly.

Beeswax or transparent wood wax is applied to those parts that are to be polished, adding layer upon layer, using a paint brush. The heated stone sucks in the wax. The next day, when the sculpture has cooled, the waxed parts are buffed to a shine by hand, using a soft cloth.

The artists explain that polishing always holds an element of surprise for them, as it makes vivid the subtle colours deep within the stone. No colouring is added – the variety of colours and patterns in the stone is all natural.

There are more than 200 documented types and shades of Zimbabwean stone. The ones used for sculpting range in hardness from about 4/10 to 8/10 – all much harder than what is what is colloquially known in the Northern hemisphere as Soapstone.

The source of these riches is the Great Dyke, a 500km ridge that is 2.5 billion years-old, abounding in mineral wealth of every description, which forms the geological backbone of Zimbabwe. It is the complex combination of these minerals that gives Zimbabwean sculptors, an unparalleled array of stone to work with.

Most sculptors work outdoors, creating and displaying their art in open-air studios. Sculpture parks are a favoured way of displaying work for sale and the country's national galleries all have sculptures parks or courtyards open to natural light.

All the sculptures exhibited here are guaranteed to withstand the Northern winter as outdoor pieces. In fact, all African Millennium sculptures come with a full guarantee and an authentication certificate.

THE ZEN OF SCULPTURE MAINTENANCE:

It is the Zen of the stone that it is both strong and fragile. While all the stone types are hard enough that they can – unless cracked – withstand the coldest temperatures, the highly polished surfaces of a sculpture can scratch, while a hard fall can cause chips on thin edges. Both the latter problems can be repaired relatively easily.

• Smooth the damaged area using, as appropriate, either a file or water paper (between 1200 and 1600 grit).

• This will leave an unwaxed surface, light in colour against the polished part.

• Evenly heat the smoothed area and its surroundings, using a heat gun, a hair dryer, or just by leaving the sculpture in front of a heater or fire.

• Take beeswax or – more simply – a commercial brand of transparent wood or floor wax. Apply the wax to the repaired area using a narrow paint brush. Note that although the waxes are branded as 'transparent', they are actually white or gold in colour.

• The heated stone will suck up the wax, so apply generously, including the immediate area around the repair, so that the wax blends into the polished surround.

• Let the stone cool and then burnish it using a clean, soft cloth. It can take a fair amount of application before a good shine is obtained because some of the surface droplets of wax have to be rubbed away completely.

•  If you want to add a base to your sculpture, it is worth noting that most of the stones drill relatively easily. One can also very easily fix the sculpture to a base or solid surface with many of the adhesives that are available at your local hardware store.