The use of materials began in the Stone Age. Typically, materials such as bone, fibers, feathers, shells, animal skin, and clay were used for weapons, tools, jewelry, and shelter. The earliest tools were in the paleolithic age, called Oldowan. These were tools created from chipped rocks that would be used for scavenging purpose. As history carried on into the Mesolithic age, tools became more complex and symmetrical in design with sharper edges. Moving into the Neolithic age, agriculture began to develop as new ways to form tools for farming were discovered. Nearing the end of the Stone Age, humans began using copper, gold, and silver as a material. Due to these metals' softness, the general use was for ceremonial purposes and to create ornaments or decorations and did not replace other materials for use in tools. The simplicity of the tools used reflected on the simple understanding of the human species of the time.