Amethyst

Hardness: 7 on Mohs scale. Color: Violet to dark purple, can show color zoning. Luster: Vitreous (glassy). Crystal Structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Amethyst forms in hydrothermal veins and cavities (geodes) within igneous rocks, particularly volcanic basalts. It crystallizes from silica-rich solutions at relatively low temperatures. The purple color is due to irradiation of iron impurities within the quartz lattice. Geologically, it can be found in rocks ranging from several million to hundreds of millions of years old.

Amethyst is primarily used as a gemstone in various forms of jewelry (rings, necklaces, earrings). Larger specimens are highly valued by mineral collectors for their aesthetic beauty. It is also used in decorative objects and spiritual practices.

The name "amethyst" comes from the Greek word "amethustos," meaning "not intoxicated," as it was believed to protect its wearer from drunkenness. Historically, it was one of the most highly prized gemstones, often equated with rubies, emeralds, and sapphires, until large deposits were found in Brazil. It is the birthstone for February.

In the field, amethyst is identified by its distinctive purple color and characteristic hexagonal crystal habit, often found lining cavities in host rocks. The color can range from a pale lavender to a deep royal purple. Common locations include Brazil (specifically Rio Grande do Sul), Uruguay, Siberia (Russia), Zambia, Bolivia, and parts of the United States (e.g., Arizona, North Carolina). When identifying, look for its glassy luster and conchoidal fracture when broken. Heat treatment can alter or remove its purple color, producing citrine (yellow/orange) or green ametrine.