Natural Magic: One of the two great divisions of Western magical practice, the other being ritual or ceremonial magic. Natural magic deals with the magical powers of physical substances—herbs, stones, resins, metals, perfumes, and the like. It has generally been much less controversial than ritual magic, and has been practiced openly even at times when even a rumor of involvement in ritual magic was enough to cause imprisonment and death.
The principle governing natural magic in the Western occult tradition is the great Hermetic axiom “As above, so below.” Every object in the material world, according to this dictum, is a reflection of astrological and spiritual powers. By making use of these material reflections, the natural magician concentrates or disperses particular powers of the higher levels of being; thus a stone or an herb associated with the sun is infused with the magical energies of the sun, and wearing that stone or hanging that herb on the wall brings those energies into play in a particular situation.
The philosophy and practice of natural magic are both closely associated with astrology and humoral medicine.
From Secrets of the Lost Symbol, by John Michael Greer