Citrine

Hardness (Mohs scale): 7. Color: Yellow, golden-yellow, brownish-yellow, or orange. Luster: Vitreous (glassy). Crystal Structure: Hexagonal (trigonal system). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Citrine is a variety of quartz. Its yellow to orange coloration is due to traces of iron within the crystal structure. Natural citrine is relatively rare and is typically formed from amethyst or smoky quartz through natural heat treatment in the Earth's crust, often in pegmatites or hydrothermal veins. Much of the citrine on the market is heat-treated amethyst, where the purple iron-containing amethyst is heated to high temperatures (around 470-560 C or 878-1040 F) to produce the yellow-orange color. The geological age of quartz deposits varies widely, from Precambrian to Cenozoic.

Primarily used as a gemstone in jewelry, including rings, necklaces, and earrings. Larger specimens are used for ornamental carvings and decorative objects. It's desired for its warm color and durability.

The name 'citrine' comes from the Old French word 'citrin,' meaning 'yellow,' which is derived from the Latin 'citrus.' Brazil is a major source of natural citrine and heat-treated amethyst. Unlike many other gemstones, citrine is not known to have specific famous specimens with unique names, but very large, high-quality faceted stones can be quite valuable. In ancient times, citrine was carried as a protection against evil thoughts and snake venom.

In the field, citrine can be identified by its characteristic yellow to orange color, its vitreous luster, and its hardness (it can scratch glass and steel). It often forms in well-defined hexagonal crystals, sometimes within geodes or in association with other quartz varieties. It is commonly found in Brazil, Bolivia, Uruguay, Argentina, Madagascar, Russia, France, and the USA (North Carolina). Collectors look for clarity, vibrant color, and well-formed crystals. Be aware that much of the citrine sold is heat-treated amethyst, which often has a more reddish-orange or brownish-orange hue compared to the paler, sometimes smoky-yellow of natural citrine.