Natural citrine is exceptionally rare. The vast majority on the market is amethyst, heated to around 300°C until its iron ions oxidise and the purple turns yellow.

Natural specimens come from Brazil, Madagascar, and Spain—particularly near Salamanca, where mining has continued since the Middle Ages. The name derives from the French ""citron,"" though the natural colour is deeper than lemon. Closer to light passing through honey.

Medieval European merchants kept the stone in their safes as a talisman for trade. Between natural and heat-treated, the mineral itself is identical. What differs is only the value people assign.