[1][7][8] However, synthetic crystals grown in iron-rich solutions have failed to replicate the color or dichroism of natural citrine.

[9] Unlike natural citrine, the color of heat-treated amethyst is known to come exclusively from trace amounts of iron oxides, specifically hematite and goethite.

Amethyst with a certain iron content can be heated to produce "madeira citrine," which has a deep orange color and exhibits red flashes.

[9] Unlike heat-treated amethyst, natural citrine typically exhibits even coloration throughout the crystal and never occurs in geodes or clusters.

Brazil is the leading producer of citrine, with much of its production coming from the state of Rio Grande do Sul.

Other notable sources include Bolivia, the Democratic Republic of the Congo, Madagascar, Mexico, Myanmar, Namibia, Peru, Russia, South Africa, the United States, and Zambia.

Queen Victoria was reportedly fond of the gemstone; many brooches and pendants featuring citrine survive from this era.

[12] Its popularity greatly increased once it was discovered citrine could be produced artificially by heating amethyst or smoky quartz.