The Kyrt is a vegetal resource in Isaac Asimov's Empire series.
About the Kyrt[]
The Kyrt is an extraordinarily valuable plant fiber, the economic foundation of the planet Sark and the source of its Galactic influence. The Kyrt is unique in the Galaxy for its properties; it can be spun into a material stronger than steel, more flexible than rubber, and capable of taking any color permanently. However, it only exhibits these miraculous properties when grown on the planet Florina.
Attempts to cultivate it elsewhere, even on Sark itself, result in ordinary, useless cellulose. This absolute dependency on Florina allowed the Sarkite Squires to establish a complete and lucrative monopoly over kyrt production, which formed the basis of their wealth and power. The entire social structure of Florina, with its oppressed native population, was built around the labor-intensive cultivation and processing of kyrt.
The potential destruction of Florina threatened this monopoly, creating the central political crisis of the novel. It was later theorized that kyrt's unique qualities were a result of biological adaptation to the specific radiation and environmental conditions of Florina's pre-nova sun. The prospect of scientists elsewhere in the Galaxy discovering how to artificially synthesize true kyrt, once they understood this causal link, was a key factor in breaking the Sarkite monopoly and enabling the evacuation of Florina.