During the Middle Ages, Chinese, Egyptian, and Islamic ideas (passed along the silk route) fused with western philosophy creating a fascinating science called alchemy. The objective of alchemy was to discover an elusive material or elixir sometimes called the "Quintessence" (the fifth element) or called the Philosopher's Stone. As understanding of metalworking increased, alchemists performed many practical experiments leading to refinements and contributions in chemistry and laboratory techniques. Though their quest for the Philosopher's Stone ultimately proved fruitless, the work of alchemists contributed to assaying techniques for purifying metals and distilling various early chemicals.