Natural citrine is a transparent variety of the quartz mineral known for its shades of yellow to light brown. This characteristic color is due to the presence of iron impurities (Fe³⁺) in its crystal structure. Citrine forms in the trigonal crystal system and has a hardness of 7 on the Mohs scale, making it relatively durable and suitable for use in jewelry.

Geologically, citrine is often found in pegmatites and hydrothermal vents, where the crystals form in cavities. It is rare in nature, and many of the stones sold as citrine are actually amethysts or smoky quartz that have been heat-treated to achieve the desired color.

Physical properties of citrine include glassy luster, conchoidal fracture, and absence of cleavage. Its density is approximately 2.65 g/cm³ and its refractive index varies between 1.544 and 1.553. Because of its transparency and brilliance, citrine is highly prized in gemology and jewelry.

Citrine is often associated with metaphysical properties, being considered a stone of prosperity and abundance. In alternative practices, citrine is said to stimulate creativity and mental clarity, although these aspects are not supported by scientific evidence.