Short answers, pulled from the story.
Archaeologists found evidence of this protein fiber in soil samples from two tombs at Jiahu in Henan province, dating back about 8,500 years. This site represents one of the earliest known uses of silk in human history.
Silk remained confined to China until the Silk Road opened sometime during the latter part of the first millennium BC. Knowledge eventually spread to Korea with technological aid around 200 BC and reached India by AD 140 before monks smuggled silkworm eggs to Constantinople around AD 550.
China produces 54% of the world's raw silk today followed by India at 14%. About 97% of India's mulberry silk comes from six states including Andhra Pradesh, Karnataka, Tamil Nadu, Bihar, and West Bengal.
Silk fibers from Bombyx mori have a triangular cross section measuring 5 to 10 micrometers wide which causes light to refract at different angles creating its signature shimmer. Tensile strength reaches 740 megapascals making it tens of times greater than poly(lactic acid) and hundreds of times that of collagen.
The process requires killing 3000 silkworms to produce just one kilogram of raw silk because harvesting kills larvae by boiling them alive. This high mortality rate continues to generate ethical debates among consumers and manufacturers worldwide.