amethyst

Amethyst is a violet variety of quartz, a mineral composed of silicon dioxide (SiO2). Its purple color arises mainly from trace amounts of iron in the crystal and exposure to natural radiation during formation. The color can range from pale lilac to deep royal purple, and within a single specimen it can vary in intensity.

Amethyst forms in a variety of geological environments, often in voids and hydrothermal veins within volcanic rocks. It is commonly found as geodes lined with quartz crystals and is frequently associated with other quartz varieties such as citrine. Crystals are typically hexagonal and may occur as long prismatic forms; the Mohs hardness of amethyst is 7, giving it durability suitable for jewelry. Its coloration can be affected by heating, which may alter or reduce the purple hue.

Historically and culturally, amethyst has been valued for decorative use in jewelry and carvings. In ancient Greece and Rome it was believed to guard against intoxication, a notion reflected in its name, which derives from the Greek amethystos meaning not drunken. It is also one of the traditional February birthstones and remains popular among gemstone collectors and jewelers.

Major sources include Brazil and Uruguay, with notable deposits in Africa (such as Zambia and Namibia) and in parts of Europe and North America. In addition to natural stones, amethyst can be produced synthetically for use in jewelry. Natural amethyst is not uniformly valuable; color zoning, clarity, and crystal form influence value. Scientific evidence does not support claimed healing properties of amethyst.