Crem was part of the rain water on Roshar. When crem was ingested it could make people sick, so one always waited one day until the crem was settled down and then took the fresh water from the top.
The crem was used to make pottery.[1] The people of Sesemalex Dar were famous for their expert crem pottery.[2]
But it had other uses as well. It was used when worming a field to close the holes after removing the worm,[1] so that no new worms could infest the field again.
Crem was used for buildings, too. Even in earlier history of Roshar, farmhouses were built of crembricks.[3] Shallan Davar considers if the buildings of Kharbranth were made of crem.[4] When the Parshendi were discovered by King Gavilar and his brother Dalinar it was observed that they made simple buildings of crem and stone.[5]
Among the problems with crem are, that if there is still crem in the drinkingwater one will get sick. Also caverns are often sealed up by crem, and another problem however is that the rainwater left icicle-like pendants of rock form on the edges of roofs. People had to clean them off regularly for avoiding that the roofs were weighing down the roof so much that it collapsed.[6]
Crem has been used as a derogatory term by several characters, i.e. "The crem of an army." or "one cremstained mark."[7]