Carbonite

Carbonite was a liquid substance that was made from carbon gas and could change into a solid through rapid freezing. Goods could be encased in carbonite for preservation, through a process known as carbon-freezing, and an example was condensed tibanna gas because carbon-freezing was used as a way to condense it for transport. Carbonite blocks could also be used to place people in hibernation. Before the invention of the hyperdrive, some early spacers would use carbonite to endure long voyages. That technique, however, had brutal side effects, collectively referred to as hibernation sickness. Droids such as the DLC-13 mining droid could be made out of heat-resistant carbonite.

-Wookieepedia