Gneiss (specifically Biotite Gneiss)
Gneiss (high-grade metamorphic rock primarily composed of Silicates)
metamorphic
Category
Sedimentary Rock (Specifically A Concretion Or Possibly A Geode)
Browse sedimentary rock (specifically a concretion or possibly a geode) specimens identified by the Rock Identifier community.
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Sandstone concretion (Ironstone-stained)
Arenite with Limonite/Hematite staining (Silica-based with Iron Oxides)
sedimentary
Conglomerate (Puddingstone)
Conglomerate (specifically, clastic sedimentary rock)
Sedimentary
Concretion
Calcareous/Siliceous Concretion
sedimentary
Quartz (chalcedony variety) or Limestone with Quartz Veins
SiO2 (for Quartz/Chalcedony); CaCO3 (for Limestone)
Mineral or Sedimentary Rock (with mineral inclusions)
Sandstone Chert Concretion
Silica-cemented Concretion (primarily SiO2)
sedimentary
Liesegang Banded Sandstone (Concretion / Weathered Pebble)
Sandstone showing Liesegang rings / Weathering rind (SiO2 with iron oxides)
sedimentary
Quartz
Quartz (SiO2 - Silicon Dioxide)
Mineral
Quartz (Druzy)
Silicon Dioxide (SiO2)
mineral
Druzy Quartz on Limestone
Silicon Dioxide (SiO2)
mineral
Banded Agate
Cryptocrystalline Silicon Dioxide (SiO2)
gemstone
Druzy Quartz
Silicon Dioxide (SiO2)
mineral
Basalt with Amygdaloidal Inclusions
Aphanitic Mafic Volcanic Rock (Basalt)
igneous
Sandstone (with potential Concretion or Fossil fragment)
Arenite (primarily SiO2)
sedimentary
Concretion
Septarian Concretion
sedimentary
Concretion
Septarian Concretion (Fragmentary)
sedimentary
Quartz Geode
Crystalline Silicon Dioxide (SiO2) within a nodule
sedimentary
Quartz-rich gravel fragment
Quartz (silicon dioxide, SiO₂), possibly with feldspar or carbonate inclusions
mineral
Red Jasper (possibly banded Jaspilite)
Silicon Dioxide with Iron Oxide (SiO2 + Fe2O3)
sedimentary
Geode (Unopened)
SiO2 (Silicon Dioxide) - Chalcedony/Quartz Geode
sedimentary
Satin Spar Selenite
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
mineral
Banded Agate (Geode Fragment)
Silicon Dioxide (SiO2) - Variety Agate
mineral
Geode (Chert/Quartz Nodule)
Silicon Dioxide (SiO2)
sedimentary
Limonite Concretion
Limonite (FeO·nH2O)
mineral
Dalmatian Jasper
Peralkaline Quartz-Feldspar Porphyry with Arfvedsonite
igneous
Bumblebee Jasper
Volcanic Tuff (mixture of Quartz, Sulfur, Hematite, and Orpiment)
igneous
Septarian Nodule (Polished)
Septarian concretion (Calcite, Aragonite, Limestone)
sedimentary
Milky Quartz Nodule / Geode precursor
Silicon Dioxide (SiO2)
mineral
Dark glassy pebble, possibly volcanic rock
Likely basalt or volcanic glass (var. obsidian), unconfirmed from image
igneous
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Quartz–mica metamorphic rock, likely schist
Quartz–muscovite/biotite schist; predominantly SiO₂ quartz with phyllosilicate micas
metamorphic
Quartz Druzy Geode
Silicon Dioxide (SiO2) - Crystalline Variety
mineral
Sandstone with Brachiopod Mold Fossil
Sedimentary rock (Sandstone) with indeterminate Brachiopod mold
fossil
Generic Pebble
Lithic Fragment
sedimentary
Red Sandstone
Arenite (SiO2 with Fe2O3)
sedimentary
Moqui Marble
Hematite-Goethite Concretion
mineral
Geode (Unopened)
Quartz Geode (SiO2-rich chalcedony/quartz nodule)
sedimentary
Unopened Geode
Geode (containing various mineralization like Quartz SiO2)
sedimentary
Light-colored limestone (probable fossiliferous or micritic limestone)
Calcite-rich carbonate rock; predominantly CaCO₃ (calcite)
sedimentary
Quartz on Host Rock
Silicon Dioxide (SiO2)
Mineral Specimen
Brecciated quartz-rich rock, possibly silicified breccia
Silica-rich breccia; chiefly microcrystalline quartz (SiO₂), with possible calcite and iron-oxide staining
sedimentary
Ironstone Concretion (likely)
Goethite/Hematite/Limonite cemented sediment
Sedimentary Rock