Amethyst
Image: <a href="//commons.wikimedia.org/wiki/User:Bultro" title="User:Bultro">Bultro</a> (CC BY-SA 4.0)
Mineral NameAmethyst
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorspurple, violet
Transparencytransparent
Type LocalityWorldwide, including Brazil, Uruguay, Siberia, Zambia, and potentially North Africa (Morocco is known for some quartz varieties).
Mineral Groupsilicates
Usesjewelry, ornamental, collector
Associated Mineralsquartz, calcite, feldspar, goethite, hematite
Raritycommon
Description
The image displays a cluster of pale to medium purple, translucent amethyst crystals, likely forming a druzy lining within a matrix. The crystals exhibit typical prismatic quartz forms.
Geological Context
Amethyst forms in hydrothermal veins and cavities (geodes) within igneous rocks, particularly basaltic lavas, and sometimes in metamorphic rocks. Its characteristic purple color is caused by irradiation of iron impurities within the quartz lattice.
