Rhyolite
Image: <bdi><a href="https://www.wikidata.org/wiki/Q108103612" class="extiw" title="d:Q108103612"><span title="Wikipedian and OpenStreetMap mapper from Cologne, Open Data activist">Raimond Spekking</span></a></bdi> (CC BY-SA 4.0)
Mineral NameRhyolite
Chemical FormulaPrimarily SiO2 (69-77 wt%) with significant Al2O3, and lesser amounts of Na2O, K2O, FeO, MgO, CaO
Mohs Hardness6
Crystal Systemamorphous
Streak Colorwhite
CleavageNone
Fractureconchoidal
Specific Gravity2.3
Colorsdark reddish-brown, dark grey, white, pink, light green
Transparencyopaque
Type LocalityMirow 1/74 deep drilling, Mecklenburg-Vorpommern, Germany
Mineral GroupIgneous Rock (Felsic Volcanic)
Usesconstruction material, decorative stone, geological study
Associated Mineralsquartz, orthoclase, plagioclase, biotite, hornblende
Raritycommon
Description
A polished core sample displaying a fine-grained, dark reddish-brown to dark grey matrix, rich in lighter-colored amygdules and phenocrysts of white, pink, and light green hues.
Geological Context
Rhyolite is an extrusive igneous rock formed from the rapid cooling of viscous, silica-rich magma, typically associated with volcanic eruptions. This sample originates from the Permian Rotliegend group in Germany, indicating ancient volcanic activity.
