This is incorrect. Mercury was a commonly used substance in alchemy due to its unique properties and symbolism in alchemical practices. It was believed to be a vital component in the transformation process of base metals into gold, a central goal in alchemical pursuits.
Alchemy began as a way to understand the natural world, particularly the properties of metals and minerals, and to search for ways to turn base metals into gold. It was also intertwined with spiritual beliefs and the quest for immortality. Over time, alchemy evolved into modern chemistry as experimental methods and scientific principles were developed.
Alchemy was traditionally practiced by alchemists, who were individuals who sought to transmute base metals into noble metals such as gold, discover the elixir of life, and create the philosopher's stone. These practitioners were a mix of philosophers, scientists, and mystics who worked in secret during the Middle Ages and early modern period.
Early experimenters with alchemy were able to create chemical compounds by trial and error.The Wizard used his alchemy to bring to back to health.
Yes, studies of alchemy date back thousands of years to a time when he difference between alchemy and chemistry were unknown. Today very few scientists study alchemy because other fields of research like physics and chemistry have more practical applications, and are somewhat easier to logically comprehend.
The purpose of alchemy was to turn common metals into valuable metals. For example - turning lead into gold
Stone+metals 
To achieve immortality, wisdom, and gold (which is what alchemy is most commonly known for)
Alchemy, generally, derives from the old French alkemie, from the Arabic al-kimia, the art of transformation. Alchemy was the attempt to turn common materials metals into precious metals or gems.
4fire + metals
Tools = wood + Metals
alien+metals+battery
Fern+metals
Metals + stone
Fire + Fire + Metals
Noria+Metals
People who practiced alchemy wished to turn lead into gold.