Banded River Rock / Gneiss (highly weathered)
Gneiss
Metamorphic rock
Category
Sedimentary Rock (Altered)
Browse sedimentary rock (altered) specimens identified by the Rock Identifier community.
Basalt with Caliche Crust
Aphanitic Mafic Igneous Rock with Calcium Carbonate (CaCO3) coating
igneous
River/Stream Pebble
Clast / Detrital Grain / Rounded Sedimentary Particle (Compositionally variable, commonly Quartz, Feldspar, Chert, or other resistant rock fragments)
Mineral, specifically a rock fragment
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Dalmatian Jasper (Dalmatian Stone)
Dalmatian Stone (primarily Feldspar, Quartz, and Arfvedsonite/Tourmaline)
igneous
Slate with Red Sandstone Landscaping Rock
Foliated Pelitic Metamorphic Rock (Slate) and Ferruginous Sandstone
metamorphic and sedimentary
Jasper and Quartzite mix
Silicon Dioxide (SiO2) with impurities
sedimentary or metamorphic
Red Sandstone
Arenite (predominantly SiO2 with Fe2O3)
sedimentary
Jasper with Quartz inclusions
Silicon Dioxide (SiO2) with varying mineral impurities
sedimentary
Quartz (Rock Crystal)
Quartz (SiO₂ - Silicon Dioxide)
Mineral
Bauxite
Alumina-rich rock (consisting of Gibbsite, Boehmite, and Diaspore)
sedimentary
Conglomerate
Conglomerate (Rock composed predominantly of rounded clasts > 2mm)
sedimentary
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) within Sedimentary/Metamorphic Matrix
Metamorphic or Igneous (context dependent)
Red Jasper
Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions
sedimentary
Fossiliferous Limestone (Coquina / Shell Limestone)
CaCO3 (Calcium Carbonate)
sedimentary
Chert / Pink Chert
Silicon Dioxide (SiO2)
sedimentary
Biotite Mica
Biotite, K(Mg,Fe)3AlSi3O10(F,OH)2
mineral
Conglomerate
Conglomerate (lithified rudite)
sedimentary
Desert Rose (Gypsum Variety)
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
mineral
Polished Rhodonite Obelisk
Rhodonite (Manganese Iron Magnesium Calcium Silicate) - (Mn,Fe,Mg,Ca)SiO3
metamorphic
Gneiss
Gneiss (High-grade metamorphic rock typically composed of Quartz, Feldspar, and Mica/Amphibole)
metamorphic
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Zebra Rock / Zebra Marble
Banded Limestone-Marble Transition
metamorphic
Quartz (vein quartz)
SiO2 (Silicon Dioxide)
Mineral
Graywacke (River Cobble)
Graywacke (Lithic Sandstone)
sedimentary
River Cobble (likely Quartzite or Limestone)
SiO2 (Quartzite dominant) or CaCO3 (Limestone dominant)
metamorphic or sedimentary
Lapis Lazuli
Lapis Lazuli (a rock composed primarily of Lazurite)
Metamorphic rock
Iron-Stained Quartzite
Recrystallized Meta-Quartzite (primarily SiO2)
metamorphic
Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock transitioned to metamorphic)
metamorphic
Chert / Flint
Chert (varieties include Flint)
Sedimentary
Quartz
Quartz (SiO₂)
Mineral
Banded Chert in Matrix
Microcrystalline Quartz (SiO2)
sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with Goethite/Iron oxide impurities
sedimentary (chemical)
Wishing Stone (Basalt/Greywacke with Quartz Vein)
Basalt or Siltstone with SiO2 (Quartz) hydrothermal intrusion
igneous/sedimentary
Quartz (Druzy Quartz)
Silicon Dioxide (SiO2)
mineral
Schist
N/A (a rock type, not a mineral formula)
metamorphic
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) within Sedimentary or Igneous Matrix
igneous
Fluorite in Matrix
Fluorite (CaF2) within a host rock matrix
Mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Quartzite Beach Pebble
Quartzite (primarily SiO2)
metamorphic
Carnelian
Chalcedony (cryptocrystalline quartz), SiO2
Mineral
Limonite (Iron Ore/Sandstone mixture)
Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix
mineral