Amethyst
Amethyst (Silicon Dioxide, SiO2)
Rock Type: mineral

Physical Properties
Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65
Formation & Geological History
Forms in hydrothermal veins or as linings inside volcanic geodes. The purple color is caused by trace amounts of iron irradiation during formation within igneous rock cavities.
Uses & Applications
Widely used for jewelry (faceted gems and beads), ornamental carvings, and decorative mineral specimens for collectors.
Geological Facts
Amethyst was considered a precious stone of equal value to diamonds until large deposits were found in Brazil in the 19th century. Its name comes from the Greek word 'amethystos', meaning 'not intoxicated'.
Field Identification & Locations
Identify by its distinct purple hue and crystal shapes. Found globally, with major deposits in Brazil, Uruguay, and Zambia. Collectors should look for deep uniform color and clarity.
Identified on: 5/13/2026
Mode: Standard