Sculpting or "modeling" in clay is user friendly and forgiving. When using clay for sculpting the human head in 3-D, use a balloon armature (make it from wood and wire). Use chicken wire as opposed to other types of wire that may be sharp and cause injury. Instructions can be found in the "Sculpting Basics" by Karin Hessenberg.
The wire supports the clay as a wire armature would be used for a figure. When working with clay, you will need the armature, clay, wooden modeling tool (large and small), potter's knife, wire strip tool, metal modeling tool, cutting wire and calipers.
Clay must be kept moist (even when not in use) or it will dry out and become brittle. If you are working on a project that requires work the next day, it is best to keep the sculpture covered with a wet cloth and under plastic cover overnight. Plaster is also an option here.
Once the sculpture is completed, use cutting wire on the backside of the head, and remove the armature before firing.
Another type of sculpture is relief (high and low) which is sculpted on a flattened ball of clay. This style was popularized by the 19th-century American sculptor Augustus Saint-Gaudens.
Early civilizations sculpted by hand using stone chisels. The monoliths at Easter Island are an example. The advent of sculpting tools made from metals such as copper, bronze and iron, eased the carving process.
When working with stone or marble, the recommended sculpting tools are drill, chisel, hammer, point and file.
Stone is a suitable material, but marble has been romanticized because of a certain Italian Renaissance artist by the name of Michelangelo.
A modern day sculpting tool would be a power tool (chainsaw). This would enable the artist to carve wood, ice, stone, or marble. An ax may be used when working with wood, but it is more labor and time intensive.
Clay is a malleable substance and can be easily reshaped. If you want a more permanent sculpture of the human face, it must be fired in a kiln at 1,000 degrees C. The clay is first put through a bisque firing. The porous clay can then be fired even further if desired, or simply glazed, painted with acrylics or polished.