Roshar

Life on Roshar has been shaped over millennia by massive, Invested storms, which pose a danger that cannot be overstated. The rainwater in highstorms is laced with a sort of slurry called crem. When crem dries, it hardens into rock. Since the highstorms always sweep from east to west, crem builds up on the eastern side of anything that stays still and isn't regularly cleaned. Over time, the continent is very slowly shifting across the planet as the highstorms cause erosion of the eastern part and a build up on the western part. The landscape of Roshar varies across its regions. Along the eastern coast, near the oceans where the highstorms originate, the land is beaten harshly by said storms, eroding away any soil, leaving rough rock formations. Almost all types of life have some type of protective shell or encasing into which they can retreat for protection. The lands in Shinovar, farthest west on the main continent of Roshar, have soil and grass that does not retract. This region is mostly protected from the highstorms by the high peaks of the Misted Mountains. Most plants that grow in Shinovar can not grow in other parts of Roshar.   Roshar's population includes several non-human races, such as the Aimians and the Parshendi, as well as many races of sentient spren.   Roshar has three moons - Salas, Nomon and Mishim, each of which waxes and wanes separately from the other. Roshar's seasons generally last only a few weeks and the world's surface gravity, at 0.7g, is significantly weaker than that of Earth. This is, in part, responsible for the exceptional growth of native creatures such as the greatshell.   The pattern of bonding spren to human is merely an expansion of what already exists in the nature of the world of Roshar. For example, gargantuan crustaceans grow to incredible size without collapsing under their own weight, not just through the nature of the world, but through symbiosis with spren. Certain animals obtain flight through similar means, and there is even a race of equines that - through the spren bond - have adapted to life on the world and obtained a high enough level of self-awareness to nearly be named a sapient species.    

Currency

The primary form of currency found on Roshar are spheres, pieces of gemstone encased in a sphere of glass with one side flattened to prevent rolling. The gemstones can be any of the ten Polestones and there are three denominations: chip, mark, and broam. The ten gemstones are organized into five value levels with some gem types having equivalent values. These value levels are determined by Soulcasting properties, so diamonds, which can create quartz, crystal, and glass, have the lowest value, and emeralds, which can create grain, have the highest. Spheres, like all gems on Roshar, have the ability to hold and leak Stormlight. Spheres with light are referred to as infused and those without are referred to as dun. Although dun spheres can be used as currency, people are suspicious of them because light is the easiest way to determine a sphere is real.