Stone Age to Metal Age: Tools, Materials, and Technological Advancements

Stone Age: The materials Palaeolithic people used to make their first tools belonged to a set of rocks and minerals with little variety, but with certain properties in common: hard, tough, fragile, and exhibiting a conchoidal fracture. The variety lies in their composition of silicon compounds. In some areas where materials were inaccessible, siliceous stems were used, such as caliza. At first, these tools were crude, but later the technique was perfected to fabricate more complex tools. In the Lower Paleolithic, fire was discovered. This allowed humans to move from simple exploitation and the precarious nature of processing activities. With Homo sapiens came the apogee of Paleolithic technology, developing "carving techniques" and using other materials such as bone, wood, ivory, and resin in the manufacture of various instruments. In the Neolithic, stone was still used, along with increasingly sophisticated instruments. Ceramic was invented, calcining clay to more than 450 degrees. Bitumen started being used as waterproofing and adhesive, and collagen obtained from animal bones was another material used as adhesive.

Metal Age: The Stone Age ends with the Neolithic period, then metallurgy begins, with technological breakthroughs that define the new cultural era. The first phase is called the Chalcolithic, in which copper is discovered and used. The second stage is the Bronze Age, when alloys of copper and tin begin to be used, and finally, the Iron Age develops.

Working with Metals: Copper, gold, and silver were the first metals worked. The reduction of copper minerals occurred after a closed furnace using charcoal in Mesopotamia. Gold was also known since ancient times and began to be worked in this era. Because of its malleability, rings, necklaces, and bracelets were obtained without actually melting it. Silver has also been used since ancient times, but it was much more rare than gold in Egypt.

Bronze: Bronze is the result of the alloy of copper and tin in variable proportions, improving the properties of copper, possessing greater hardness and a lower melting point. These features made it useful for 2000 years in the manufacture of weapons and other utensils. It is assumed that the Egyptians were the first to add tin to copper to note that this gave better results. In this era, iron was known as a metal harder than bronze. When metal pieces were beaten, arms were obtained that were harder and more resistant than brass and that, besides, maintained their edge longer. The first iron used by our ancestors was obtained from meteorites, was alloyed with nickel, cobalt, and was much harder than bronze. Iron is abundant in nature and is drawn from a more complicated process than copper, needing temperatures of 1536 degrees.