Amethyst
Image: <bdi><a href="https://www.wikidata.org/wiki/Q18508147" class="extiw" title="d:Q18508147"><span title="German photographer">Engelbert Reineke</span></a></bdi> (CC BY-SA 3.0 de)
Mineral NameAmethyst
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorspurple, violet
Transparencytransparent to translucent
Type LocalityWorldwide, commonly Brazil and Uruguay for geodes
Mineral GroupSilicates
Usesjewelry, ornamental, collector
Associated Mineralscalcite, zeolites, goethite, hematite
Raritycommon
Description
The image displays a collection of various minerals and fossils, prominently featuring several amethyst geodes with their characteristic purple crystalline interiors, alongside other rough mineral specimens and a large ammonite fossil.
Geological Context
Amethyst, a variety of quartz, typically forms in hydrothermal veins or within the gas cavities (geodes) of volcanic rocks. The purple coloration is attributed to iron impurities and natural irradiation. The collection also includes fossils, indicating sedimentary or metamorphic origins for those specimens.
