Currency

Money on Roshar comes in the form of spheres: glass beads a little larger than a thumbnail with a small cut gemstone set at the center. Highstorms infuse those gemstones with Stormlight, so a purse of coins doubles as a lamp, and the light holds for about a week before it fades. A sphere that has gone dark is called dun, and it spends at exactly the same value as a glowing one. Denomination depends on the stone at the center rather than the glass around it. Chips are the smallest, five chips make a mark, and four marks make a broam. Type matters as much as size, since different gemstones suit different uses, and most spheres are flattened on one side so they do not roll away when set down.