Alchemy is a precursor to modern chemistry that was widely practiced all over the world through the 1800s, when more modern chemistry began to displace it. This discipline involved a study of the chemical properties of various substances, with a mystical bent. Ancient alchemists laid the groundwork for the scientific field of chemistry, establishing some basic principles which continue to be used today. They also discovered a number of things with practical applications, from some of the elements to the chemical process used to tan leather.
The practice of alchemy appears to be quite ancient. The Egyptians, Greeks, Romans, Chinese, and early Arab community all engaged in alchemical investigations, and some exchange of information between these groups seems to have occurred as well. Alchemists had a number of goals in their work, and many of them were looking for a process that would turn base metals like lead into gold or silver. They also pursued a panacea, also known as a cure-all, that would theoretically extend life indefinitely. Needless to say, none of these pursuits were successful, but alchemists did stumble upon a number of things along the way.
In Europe, alchemy experienced a resurgence during the medieval era, thanks to an interest in translating ancient texts that exposed people to the concept. In addition to being an exploration of chemistry, medieval work was also about philosophy and metaphysics, and as chemistry began to emerge as a separate discipline, the exploration of alchemy turned metaphysical. People who view this practice as metaphysical believe that alchemical terms are metaphors, rather than literal references to substances.
The term is Arabic in origin, being derived from al-kimya, which means “chemistry.” Alchemy is also sometimes called the spagyric art, in a reference to Greek words which mean “to separate” and “to join.” Many alchemists devoted themselves to separation and purification of various substances in pursuit of their goals, and in the medieval era, this took on a new level of complexity as people searched for the philosopher's stone, rather than trying to directly transform metals into gold and so forth. These alchemists believed that the philosopher's stone was the vital tool that would be needed to create a panacea or to transmute metals into gold, because the stone would somehow enhance their knowledge.
Because alchemy uses a wide variety of esoteric terms and symbols, many people of a mystical bent have become intrigued by it. It is often studied along with astrology, another earlier version of a modern scientific discipline. Many examples of alchemical texts can be seen on display in museums, and some bookstores carry reproductions of such books for people who are interested in this field of study.