Silk is a natural fiber that is usually woven into textiles. The protein fiber of silk is composed from cocoons of the larvae of mulberry silkworms. The shiny appearance of silk comes from the complex structure of the fiber, which refracts light. In the past silk was considered to be an expensive product suited only for nobility and imperial families and was highly valued. The famed Silk Road from Kyoto through China to Turkey was not only used for silk but also for other goods, in early trading. Japan, China and Thailand are the world's largest producer of silk.