According to an article by Joe Schwarcz, PhD, published by McGill University’s Office for Science and Society, rayon is the first synthetic fiber. Until the late 19th century, you must be moneyed to enjoy the luxury of silk. After all, 5000 silkworm cocoons are needed to produce a kilo of the fiber, not to mention the labor-intensive process that went into harvesting, extracting, and spinning them. All that made silk very expensive.