Greywacke (likely)
Greywacke (a type of sandstone)
Sedimentary
Category
Man Made (Synthetic Rock)
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Quartz vein in dark host rock
Quartz (SiO₂), likely in basalt, gabbro, or altered mafic rock
mineral
Sandstone (lithic wacke)
Arenite / Lithic Wacke (mostly SiO2 with rock fragments)
sedimentary
Pumice and Scoria
Vesicular Volcanic Rock (Pumice: Silicic / Scoria: Mafic)
igneous
Basalt with Weathering Rind
Basalt (Mafic Volcanic Rock)
igneous
Sandstone
Arenite
Sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Basalt with Quartz Vein
Basaltic rock with hydrothermal SiO2 filling
igneous
Porphyritic Basalt
Porphyritic Basalt (with Plagioclase phenocrysts)
igneous
Porphyritic Basalt (with Pyrolusite or Iron-oxide staining)
Porphyritic Basalt (Mafic Extrusive)
igneous
Basalt
Basalt (Mafic volcanic rock)
igneous
Sandstone
Arenite (primarily SiO2)
sedimentary
Unidentified Rock
Unknown
sedimentary
Sandstone (likely Arkosic)
Clastic Sedimentary Rock
sedimentary
Orange Quartz (or Carnelian Chalcedony)
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite (SiO2 based with various mineral cements)
sedimentary
Petrified Wood
Silicified wood (primarily quartz, SiO2)
fossil
Fossilized Bark
Lepidodendron / Sigillaria fossil impression
fossil
River Pebble (likely Quartzite or Siltstone)
Sedimentary Clast (SiO2 based)
sedimentary
Quartz with Host Rock
Silicon Dioxide (SiO2)
mineral
Granite Cobble
Intrusive Igneous Rock (Felsic to Intermediate)
igneous
Basalt
Extrusive Igneous Rock
igneous
Basalt
Extrusive Igneous Rock
igneous
Granite
Intrusive Igneous Rock
igneous
Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
metamorphic
Banded Greywacke
Greywacke (Lithic wacke)
sedimentary
Granite
Plutonic felsic rock (Quartz, Feldspar, Mica)
igneous
Slate
Foliated Metamorphic Rock (Mainly composed of Quartz, Illite, Chlorite)
metamorphic
Quartz Geode (likely within Limestone or Dolomite matrix)
Quartz (SiO₂)
Mineral within a Sedimentary Rock
Light-colored granite or granitic gneiss
Granite; typically quartz + feldspar + mica (variable composition)
igneous
Weathered iron-rich rock, likely limonite/goethite-bearing laterite
Limonite–goethite aggregate, commonly approximated as hydrated iron oxides (FeO(OH)·nH₂O)
mineral
Basalt with Amygdales
Amygdaloidal Basalt
igneous
Basalt with Quartz Veining
Veined Basalt (composed primarily of plagioclase feldspar, pyroxene, and olivine with quartz/calcite infill)
igneous
Basalt with Quartz/Calcite Veins
Amygdaloidal Basalt (SiO2 or CaCO3 inclusions)
igneous
Basalt with Calcite Veins
Basalt (containing CaCO3 inclusions)
igneous
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Sandstone (River Cobble)
Sandstone (principally composed of Quartz, SiO2)
sedimentary
Quartz Pebble (Feldspathic / Chert Pebble)
Silicon Dioxide (SiO2) / Potassium Feldspar (KAlSi3O8)
sedimentary
River-worn Chert
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone (Micaceous)
Clastic Sedimentary Rock (primarily SiO2 with Mica)
sedimentary
Sandstone
Arenite (predominantly SiO2 quartz grains)
sedimentary
Pebble (likely Sandstone or Granitic Pebble)
Clastic Sediment (or specific rock type, e.g., Arenite, Granitoid Pebble)
Rock (likely Sedimentary)