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A variety of quartz that is crystalline and usually yellow but sometimes red-brown to red-orange. It is uncommon in nature; most yellow stones sold as citrine are smoky quartz or amethyst that have had the colour changed by heat treatment.
Natural citrine always shows dichroism, which is absent in heat-treated yellow quartz. The main source of citrine is Brazil, where it is often confused with yellow topaz also found there, and hence the latter has locally been called ‘Brazilian topaz’ to distinguish it from the yellow quartz. The prefix ‘Brazilian’ should be discarded as confusing, and also such misnomers as ‘Occidental topaz’, ‘Spanish topaz’, and ‘false topaz’.
The name ‘citrine’ is derived from the French word citron (lemon), the colour that it usually exhibits.