Citrine – natural minerals and cut stones

Citrine – the yellow to orange variety of natural quartz

Citrine is a yellow, golden-yellow to orange-brown variety of quartz with the chemical composition SiO₂. Its color is primarily related to trace amounts of iron within the crystal structure and to the geological conditions present during its formation. The name citrine is derived from the Latin word citrus, referring to its lemon-yellow color.

Natural citrine is relatively rare compared with amethyst or rock crystal. It most commonly displays delicate pale-yellow, honey-colored, golden or smoky-yellow shades. It may form as individual crystals, crystal groups or sections within quartz veins. Some specimens show gradual transitions between citrine and smoky quartz.

Thanks to its hardness, durability and attractive color, citrine is a popular gemstone and collector's mineral. High-quality transparent material is cut into faceted gemstones, while natural crystals and druses are valued as mineralogical specimens.

How citrine forms

Citrine forms in silica-rich geological environments, particularly in hydrothermal veins, pegmatites and cavities within various rocks. It crystallizes from silica-rich fluids in a similar way to rock crystal, amethyst and smoky quartz. Its final color is influenced by the iron content, the position of iron within the crystal lattice and natural temperature or radiation conditions during crystal growth.

Natural citrine may be evenly colored, but it often displays subtle color zoning. Transitions between yellow and smoky-brown areas occur in crystals that are mineralogically closely related to smoky quartz. In rare cases, one crystal may contain both violet amethyst zones and yellow citrine zones; this variety is known as ametrine.

In addition to natural citrine, heat-treated amethyst is commonly offered on the market. Heating can produce yellow to orange-brown colors. Natural citrine is usually lighter and softer in tone and generally does not display the intense burnt-orange coloration typical of many heat-treated specimens.

Major citrine localities

Natural citrine occurs in a number of quartz deposits, although high-quality crystals with natural yellow coloration are considerably less common than other quartz varieties.

• Brazil: the world's most important source of citrine, amethyst and ametrine, particularly in Minas Gerais and Rio Grande do Sul.
• Bolivia: best known for the Anahí deposit, where natural citrine and ametrine occur.
• Madagascar: produces natural crystals in honey, golden-yellow and smoky-yellow shades.
• Democratic Republic of the Congo: known for collector-quality crystals of natural citrine and citrine-colored smoky quartz.
• Zambia, Namibia and Russia: additional localities where naturally yellow to smoky-colored quartz is found.