Silk (3000 BCE)

Silk cultivation remains China’s most lucrative ancient monopoly: it generated over 3 billion Chinese yuan annually along the Silk Road alone. The Chinese imperial court guarded sericulture so zealously that revealing silkworm secrets was punishable by death, a secrecy that outperforms #2 Cast Iron's 1,000-year technological lead by a margin of 2,000 years. This fabric, derived from Bombyx mori cocoons spun at 15 cocoons per gram of silk, weighed 30% lighter than comparable woolen cloth from the Han dynasty, revolutionizing global trade from 3000 BCE onward.