Item from The Stormlight Archive by Brandon Sanderson
Gemstones infused with Stormlight during highstorms — serving as currency, light source, and fuel for Surgebinding and fabrials. Ten polestone types, each associated with an essence.
Gemstones are Roshar's everything. Currency, infrastructure, and magical fuel all in one. Highstorms infuse exposed gems with Stormlight, which slowly leaks over about a week. Infused gems light homes, power fabrials, fuel Surgebinding, and serve as money — the denomination determined by size (chip, mark, broam) and type. Emeralds are most valuable because they're used in Soulcasting food. The gemstone economy creates unique pressures. Gems must be regularly re-infused during highstorms, creating a natural economic cycle. Perfect gemstones — flawless stones that hold Stormlight indefinitely — are astronomically valuable and cosmere-significant. The entire Rosharan economy is essentially powered by regular apocalyptic storms, which is the most Rosharan thing imaginable.
Cut gemstones ranging from broam-sized (large, high denomination) to chips (tiny, low denomination). When infused, they glow with inner light in their gem color — sapphires blue, rubies red, emeralds green. The light fades over days as Stormlight leaks. Dun (depleted) gems are dull and nearly worthless as currency.
Also known as: gemstones, spheres, broams