The modern mirror was invented in 1835 by German chemist Justus von Liebig. However, people have been using various polished stones and metals as mirrors for at least 8,000 years.
In a LiveScience article, Dr. Jay Enoch reviewed the evidence and determined that people in what is now Turkey used polished obsidian as mirrors about 8,000 years ago. Other variations of metals and polished materials served as early mirrors throughout the world. Polished copper was popular in Iraq and Egypt, while early South Americans used polished stones. Other cultures, including societies in India, used bronze.
Glass mirrors did not become popular until the 19th century, when Justus von Liebig applied silver to one side of a pane of glass and created the modern mirror.