The series premiered on demand on November 23, 2015, and on Syfy on December 14, 2015. A 13-episode second season premiered on February 1, 2017. In March 2017, Syfy renewed The Expanse for a 13-episode third season to air in 2018.
Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian.
The volcanic glass, or perlite, is formed when lava (molten rock) spews out of a volcano, and cools in a rapid manner. Because of rapid cooling, water is trapped within the rock, and the lava forms into a glass-like structure.