If the Stone Age ended conclusively the moment the first human smelted copper from copper ore, then how do historians classify the thousands of years between that moment and the traditional beginning of the Bronze age?
Stone age: 2.5 million years ago – 9000 BCE
Golden age: Isaac Asimov speculated that gold was the “first metal.” His reasoning is that gold by its chemistry is found in nature as nuggets of pure gold. In other words, gold, as rare as it is, is always found in nature as the metal that it is. Almost all other metals are found in ores, a mineral bearing rock, that require heat or some other process to liberate the metal. Another feature of gold is that it is workable as it is found, meaning that no technology is required beyond our human eyes to find it. Thus, a gold nugget, a stone hammer, and a stone anvil to work the metal was all that they needed. The earliest Stone age tools were stone, bone, wood, and sinew. These sufficed to work gold.
Soon after the discovery of gold, we can assume while out searching for gold, copper was discovered.
Copper has a history of use that is at least 10,000 years old; estimates of its discovery place it around 9000 BCE in the Middle East. The earliest use of bronze places the start of the Bronze Age around 3600 BCE.
Copper occurs naturally as native copper and was known to some of the oldest civilizations on record. It has a history of use that is at least 10,000 years old, and estimates of its discovery place it at 9000 BC in the Middle East. Pure copper is soft and malleable; a freshly exposed surface has a reddish-orange color.
Copper was the first metal in common use for tools and containers since it is one of the few metals available in non-oxidized form, not requiring the smelting of an ore. Copper is easily softened by heating and then cooling (it does not harden by quenching, as in cool water). In this annealed state it may then be hammered, stretched and otherwise formed, progressing toward the desired final shape, but becoming harder and less ductile as work progresses. If work continues beyond a certain hardness the metal will tend to fracture when worked and so it may be re-annealed periodically as the shape progresses. Annealing is stopped when the work-piece is near its final desired shape, and so the final product will have a desired stiffness and hardness. The history of copper metallurgy is thought to have followed the following sequence:
Bronze age: 3600 – 1300 BCE
Tin, or the discovery of tin, resulted from an unintentional alloying due to an unknown trace metal content in some copper ore. The addition of this second metal (tin) to copper increased its hardness, lowered its melting temperature, and improved the casting process by producing a more fluid melt that cooled to a denser, less spongy metal. Cassiterite (SnO2), the tin oxide form of tin, was most likely the original source of tin discovered in ancient times. This was the important innovation that allowed for much more complex shapes cast in closed molds. As a result of this accidental discovery, tin was added into the molten copper and bronze was born. Bronze is an alloy of copper and tin. Bronze was an important advance because it had the edge-durability and stiffness that pure copper lacked and brought about the Bronze Age. Until the advent of iron, bronze was the most advanced metal for tools and weapons in common use.
Iron age: 1300 BCE
Between 1300 BCE and 1000 BCE, diffusion in the understanding of iron metallurgy and utilization of iron objects became vast and far-flung.
So why is there a three age system – Stone age, a Bronze age, and an Iron age?
The concept of dividing pre-historical ages into systems based on metals extends far back in European history, but the present archaeological system of the three main ages: stone, bronze and iron, originates with the Danish archaeologist Christian Jürgensen Thomsen (1788–1865), who placed the system on a more scientific basis by typological and chronological studies, at first of tools and other artifacts present in the Museum of Northern Antiquities in Copenhagen (later the National Museum of Denmark). He later used artifacts and the excavation reports published or sent to him by Danish archaeologists who were doing controlled excavations. His position as curator of the museum gave him enough visibility to become highly influential on Danish archaeology. A well-known and well-liked figure, he explained his system in person to visitors at the museum, many of them professional archaeologists.
He showed that artifacts could be classified into types and that these types varied over time in ways that correlated with the predominance of stone, bronze or iron implements and weapons. In this way he turned the Three-age System from being an evolutionary scheme based on intuition and general knowledge into a system of relative chronology supported by archaeological evidence. Initially, the three-age system as it was developed by Thomsen and his contemporaries in Scandinavia, such as Sven Nilsson and J.J.A. Worsaae, was grafted onto the traditional biblical chronology. But, during the 1830′s they achieved independence from textual chronologies and relied mainly on typology and stratigraphy.
In 1881 John Evans recognizing that the use of copper often preceded the use of bronze distinguished between a transitional Copper Age and the Bronze Age proper. He did not include this transitional period in the tripartite system of Early, Middle and Late Bronze Age but placed it at the beginning outside of it. He did not, however, present it as a fourth age, but chose to retain the traditional three-age system.
In 1884 Gaetano Chierici, perhaps following Evans’ lead, renamed it in Italian as the “Bronze-stone” transition. This phrase never meant that the period is one in which both bronze and stone were used. The Copper Age features the use of copper, excluding bronze; moreover, stone continued to be used in a minor industry throughout both the Bronze Age and the Iron Age. “Litica” simply names the Stone Age as the point from which the transition began and is not another -lithic age. The Neolithic was never part of the Stone Age, which ended conclusively the moment the first smelter succeeded in obtaining copper from copper ore for the first time.