Crick

Mass Effect 2 & Mass Effect 3
Known for its spectacular geysers that can be seen from orbit, Crick is a rock planet with expansive frozen oceans. Though it is within the temperature and pressure range for human habitation, its thick atmosphere is largely carbon dioxide and monoxide, making breath masks or environmental suits mandatory. The most abundant resources for exploitation are the potassium salts found in its seabeds, which fetch good prices on terraforming worlds.