5,000 years ago, humanity transitioned from the Stone Age to the Bronze Age thanks to the advent of metallurgy, which allowed for the extraction of metals from ores.
Today, alloys are present in everything from smartphones to spacecraft. These are the latest products of metallurgical activities that have existed since the Bronze Age, when the first metal mixtures were created. Nowadays, mining and processing metals is a large industry, but early pioneers worked with metals using only stone tools and ordinary fire.
The creation of the bronze-tin alloy is one of the most significant advancements in world history. (Image: Anna Kepa)
Initially, prehistoric people could only mine metals in their native form, meaning they existed as lumps and were not mixed with other elements in rocks. Therefore, they did not require extraction processes and could be collected by panning in rivers or digging in the ground.
The oldest bronze artifacts date back about 8,000 years, while gold items appeared a few thousand years later. At this time, the technology needed to extract iron from ores had not yet developed, although ancient Egyptians had fashioned some objects from meteorite iron. They could transform these into daggers like the one found in the tomb of Pharaoh Tutankhamun.
Images of both sides of the dagger from the tomb of King Tutankhamun taken in 2020 and when it was first discovered in 1925 (bottom). (Image: Meteoritics & Planetary Science/Harry Burton).
About 5,000 years ago, humans began transitioning from the Stone Age to the Bronze Age, largely due to the development of metallurgy. This process involved heating copper ore in stone or ceramic pots to separate the metal from impurities.
While there are no records of how metallurgy originated, it is likely that ancient people had the idea of blowing air through hollow rods to increase the furnace temperature, helping to release molten metal. These primitive blacksmiths did not realize that carbon from wood reacted with oxygen in the ore, converting it to CO2 and releasing the copper that was bonded to it.
Copper is a suitable metal for use, enabling the creation of tools and weapons far superior to those made of stone. Copper hardens when struck with a hammer and can be melted and poured into molds for standardized production.
Additionally, copper can be significantly enhanced by mixing it with tin to form a new alloy. This metal mixture is not only harder than pure copper when hammered but also melts at a much lower temperature, making the casting process easier.
The widespread use of this mixture around 3000 BCE marked the beginning of the Bronze Age—a period when many alloys were created as humans experimented by adding zinc and other metals to copper. In fact, this experimentation has never ceased. New alloys continue to emerge with various useful applications.
The technological advancements of the Bronze Age propelled the most powerful civilizations of the ancient world. However, this era eventually came to an end when humans discovered how to smelt iron from ore, creating a material that was even more useful and ushering in the Iron Age.
Initially, ancient furnaces could not reach high enough temperatures to actually melt iron. Thus, the first blacksmiths had to work with wrought iron—a material obtained by separating it from the slag produced during the smelting process. By around 300 BCE, Chinese metalworkers invented a type of bellows capable of producing flames hot enough to melt iron.
Interestingly, iron is actually not as hard as the bronze-tin alloy; objects made from iron are often of lower quality than those made from the previous alloy. However, the production of iron is much cheaper than this alloy, primarily due to the abundance of iron compared to tin. Later on, iron was also used to create steel—one of the most essential materials in modern times.
