Still Water as Mirrors
Our prehistoric ancestors probably took a pool of still water as a mirror, or collect water with a primitive vessel and look into the vessel to check their reflection for thousands and millions of years before polished obsidian was used as a mirror.
Polished Stone as Mirrors
The earliest physical mirrors that people could hold in hands were pieces of polished stone such as obsidian coming from volcanic eruptions. People would heavily polish the stone until it shows a beautiful reflection, making it the world’s first mirror. However, as you may perceive, theses obsidian mirrors were really heavy, so they usually weren’t made large. They were mainly used as small decorations by the wealthy. Legend has it that the peoples of ancient Mexico used polished obsidian mirrors as instruments of black magic. By gazing into a mirror’s smoky depths, sorcerers can travel to the world of gods and ancestors.
Examples of obsidian mirrors found in Anatolia (modern-day Turkey) have been dated to around 6000 BC. Other polished stone mirror examples were from Central and South America date from around 2000 BC. The earliest mirrors one can hold in hands in China were made from polished jade.
Polished Metal as Mirrors
By the Bronze Age most regions were using mirrors made from polished plates of bronze, copper, silver, or other metals. Such metal mirrors were always there throughout the Middle Ages in Europe. During the Roman Empire, silver mirrors were in common use by servants.
However, common metal mirrors tarnished easily and required frequent polishing, but even heavily polished, theses mirrors still had low reflectivity. Most ancient metal mirrors had a round shape, and their backside was usually embellished with delicate and beautiful ornamentation.