The word alchemy derives from the Old French alquimie, which is from the Medieval Latin alchimia, and which is in turn from the Arabic al-kimia (الكيمياء). This term itself is derived from the Ancient Greek chemeia (χημεία) with the addition of the Arabic definite article al- (الـ). It used to be thought that the ancient Greek word was originally derived in its turn from "Chemia" (Χημία), a version of the Egyptian name for Egypt, which was itself based on the Ancient Egyptian word kēme (hieroglyphic Khmi, black earth, as opposed to desert sand). Some now think that the word originally derived from chumeia (χυμεία) meaning "mixture" and referring to pharmaceutical chemistry. With the later rise of alchemy in Alexandria, the word may have been mistakenly thought by ancient writers to derive from Χημία, and thus became spelled as χημεία, and the original meaning forgotten. The question of the etymology of the word alchemy is still open, and recent research indicates that the Egyptian derivation of the word may be valid. 
Alchemy became known as the spagyric art after Greek words meaning to separate and to join together in the 16th century, the word probably being coined by Paracelsus. Compare this with one of the dictums of Alchemy in Latin: Solve et Coagula — Separate, and Join Together (or "dissolve and coagulate").
The best-known goals of the alchemists were the transmutation of common metals into gold (called chrysopoeia) or silver (less well known is plant alchemy, or "spagyric"); the creation of a "panacea", or the elixir of life, a remedy that, it was supposed, would cure all diseases and prolong life indefinitely; and the discovery of a universal solvent. Although these were not the only uses for the discipline, they were the ones most documented and well-known. Certain Hermetic schools argue that the transmutation of lead into gold is analogical for the transmutation of the physical body (Saturn or lead) into (Gold) with the goal of attaining immortality. This is described as Internal Alchemy. Starting with the Middle Ages, Persian and European alchemists invested much effort in the search for the "philosopher's stone", a legendary substance that was believed to be an essential ingredient for either or both of those goals. Pope John XXII issued a bull against alchemical counterfeiting, and the Cistercians banned the practice amongst their members. In 1403, Henry IV of England banned the practice of Alchemy. In the late 14th century, Piers the Ploughman and Chaucer both painted unflattering pictures of Alchemists as thieves and liars. By contrast, Rudolf II, Holy Roman Emperor, in the late 16th century, sponsored various alchemists in their work at his court in Prague, one of which was a particular alchemist named Edward Kelley.
It is a popular belief that Alchemists made contributions to the "chemical" industries of the day—ore testing and refining, metalworking, production of gunpowder, ink, dyes, paints, cosmetics, leather tanning, ceramics, glass manufacture, preparation of extracts, liquors, and so on (it seems that the preparation of aqua vitae, the "water of life", was a fairly popular "experiment" among European alchemists). Alchemists contributed distillation to Western Europe. The double origin of Alchemy in Greek philosophy as well as in Egyptian and Mesopotamian technology set, from the start, a double approach: the technological, operative one, which Marie-Louise von Franz call extravert, and the mystic, contemplative, psychological one, which von Franz names as introvert. These are not mutually exclusive, but complementary instead, as meditation requires practice in the real world, and conversely.
Several early alchemists, such as Zosimos of Panopolis, are recorded as viewing alchemy as a spiritual discipline, and, in the Middle Ages, metaphysical aspects, substances, physical states, and molecular material processes as mere metaphors for spiritual entities, spiritual states, and, ultimately, transformations. In this sense, the literal meanings of 'Alchemical Formulas' were a blind, hiding their true spiritual philosophy, which being at odds with the Medieval Christian Church was a necessity that could have otherwise led them to the "stake and rack" of the Inquisition under charges of heresy. Thus, both the transmutation of common metals into gold and the universal panacea symbolized evolution from an imperfect, diseased, corruptible, and ephemeral state towards a perfect, healthy, incorruptible, and everlasting state; and the philosopher's stone then represented a mystic key that would make this evolution possible. Applied to the alchemist himself, the twin goal symbolized his evolution from ignorance to enlightenment, and the stone represented a hidden spiritual truth or power that would lead to that goal. In texts that are written according to this view, the cryptic alchemical symbols, diagrams, and textual imagery of late alchemical works typically contain multiple layers of meanings, allegories, and references to other equally cryptic works; and must be laboriously "decoded" in order to discover their true meaning.
In his Alchemical Catechism, Paracelsus clearly denotes that his usage of the metals was a symbol:
Q. When the Philosophers speak of gold and silver, from which they extract their matter, are we to suppose that they refer to the vulgar gold and silver?
A. By no means; vulgar silver and gold are dead, while those of the Philosophers are full of life.
Alchemical symbolism has been occasionally used by psychologists and philosophers. Carl Jung reexamined alchemical symbolism and theory and began to show the inner meaning of alchemical work as a spiritual path.
Jung saw alchemy as a Western proto-psychology dedicated to the achievement of individuation. In his interpretation, alchemy was the vessel by which Gnosticism survived its various purges into the Renaissance, a concept also followed by others such as Stephan A. Hoeller. In this sense, Jung viewed alchemy as comparable to a Yoga of the East, and more adequate to the Western mind than Eastern religions and philosophies. The practice of Alchemy seemed to change the mind and spirit of the Alchemist. Conversely, spontaneous changes on the mind of Western people undergoing any important stage in individuation seems to produce, on occasion, imagery known to Alchemy and relevant to the person's situation.
His interpretation of Chinese alchemical texts in terms of his analytical psychology also served the function of comparing Eastern and Western alchemical imagery and core concepts and hence its possible inner sources (archetypes).
Marie-Louise von Franz, a disciple of Jung, continued Jung's studies on Alchemy and its psychological meaning.