Amethyst

Hardness: 7 on Mohs scale. Color: Violet to purple, ranging from pale lilac to deep purple. Can exhibit color zoning. Luster: Vitreous (glassy). Crystal Structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Amethyst typically forms in hydrothermal veins within igneous rocks or in geodes. Silica-rich fluids containing iron trace elements crystallize at moderate temperatures and pressures. The purple color is due to irradiation within the crystal structure, causing the iron impurities to become color centers. Geological Age: Various, found in formations from Precambrian to Cenozoic.

Predominantly used as a gemstone in jewelry (rings, necklaces, earrings). Also used for decorative objects, carvings, and as collectible mineral specimens. Historically, it was used in royal regalia and religious artifacts.

Amethyst is the most prized variety of quartz. Its name comes from the Greek word 'amethystos', meaning 'not drunk', as it was believed to protect its owner from intoxication. The largest amethyst geode ever found weighed over 13 tons. Heat treatment can change the color of amethyst to yellow, producing citrine, or green, known as 'green amethyst' or prasiolite.

Identify by its characteristic purple color, vitreous luster, and hardness (it can scratch glass). Found worldwide, with significant deposits in Brazil (known for large geodes), Uruguay, Siberia (Russia), Zambia, Bolivia, Canada, and the United States (North Carolina, Arizona). In the field, look for hexagonal crystal points or geode interiors within volcanic rocks or pegmatites. Collectors look for deep, even coloration and well-formed crystals.