Plant alchemy, or spagyrics, was the practice of extracting the essences of plants and herbs through alchemical methods, and then using said essences to create medicines, potions, and/or healing ointments. This tied in very closely with astrology, so far as that every plant, to the Medieval alchemist, corresponded to a specific planet in the solar system. Therefore, if an alchemist wished to make a potion to say, help attract love, he would use herbs such as foxglove, mugwort or vervain, since those herbs were considered "sacred to (i.e. corresponding to) the planet Venus." Mineral alchemy would also fall neatly into the astrological fold, with metals such as iron and lead being considered sacred to the planets Mars and Saturn, respectively.
Free eBooks (Can Be Downloaded):
Barbara Obrist - Visualization In Medieval AlchemyRoger Bacon - The Mirror Of Alchemy
Aleister Crowley - Alice An Adultery
Charles Webster Leadbeater - Occult Chemistry
Arthur Edward Waite - What Is Alchemy