Gneiss (specifically a granitic gneiss cobble)
Gneiss (high-grade regional metamorphic rock)
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.
Learn about Sedimentary Rock (Specifically A Concretion Or Possibly A Geode) in the encyclopedia
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Crazy Lace Agate
Chalcedony (Silicon Dioxide, SiO2)
mineral
Quartz Geode
Crystalline Silicon Dioxide (SiO2)
mineral
Shale with Vein Infillings
Shale (a fine-grained clastic sedimentary rock). The veins could be Calcite (CaCO3), Quartz (SiO2), or other minerals.
Sedimentary Rock
Ironstone (Limonite/Goethite Concretion)
Ferruginous Sedimentary Rock (composed of Goethite FeO(OH) and Limonite)
sedimentary
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Chert (Jasper variety)
Silicon Dioxide (SiO2)
sedimentary
Pebble
Lithic fragment / Weathered rock fragment
sedimentary
Sandstone (Banded)
Arenite (primarily SiO2)
sedimentary
Stromatolite
Laminated biogenic sedimentary structure (formed by Cyanobacteria)
sedimentary
Dyed Agate Geode
Silicon Dioxide (SiO2) - Chalcedony variety
mineral
Quartz-rich rock, possibly milky quartz or quartzite fragment
Quartz (SiO₂), potentially quartzite if metamorphic
mineral
Brecciated Jasper
Silicon dioxide (SiO2) microcrystalline quartz breccia
sedimentary
Weathered iron-rich rock, possibly hematite-bearing breccia
Hematite (Fe₂O₃)-rich lithic fragment; exact host rock is uncertain from the image
mineral
Unknown Tumbled Stone
Unknown (Too Blurry)
mineral
Smoky Quartz and Chalcedony Geode Fragment
Silicon Dioxide (SiO2)
mineral
Quartz Geode or Druzy Quartz in Host Rock
Silicon Dioxide (SiO2)
mineral
Rounded reddish-brown pebble
Likely ferruginous sandstone or iron-rich quartzite; exact identification requires a fresh surface and tests
sedimentary
Sandstone Concretion
Clastic Sedimentary Concretion (typically Quartz/Silica with Iron Oxide)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Basalt
Basalt (Mafic volcanic rock)
igneous
Marble
Recrystallized Calcite (CaCO3) or Dolomite (CaMg(CO3)2)
metamorphic
Chalcedony
Silicon dioxide (SiO2)
mineral
Shale (possibly Carbonaceous or Oil Shale)
Laminated Mudstone (primarily clay minerals and quartz)
sedimentary
Chert (Jasper variety)
Microcrystalline Quartz (SiO2)
sedimentary
Dalmatian Stone
Dalmatian Jasper (Aplitic Rock)
igneous
Foliated Metamorphic Rock (likely Gneiss or Schist)
Gneissic Metamorphic Rock
metamorphic
Pebble
Lithic fragment (Quartzite or general rock pebble)
sedimentary
Celestite
Celestine (SrSO4)
mineral
Citrine
Crystalline Quartz (SiO2) with iron impurities
mineral
Hag Stone
Perforated Sedimentary Rock (typically Limestone or Sandstone)
sedimentary
Clear Quartz
Silicon dioxide (SiO2)
mineral
Dyed Agate
Silicon Dioxide (SiO2) with artificial pigment
sedimentary
Blue Chalcedony
Chalcedony (SiO2)
mineral
Quartz / Chalcedony Geode Fragment
Silicon Dioxide (SiO2)
mineral
Fossil Coral
Hexagonaria or Rugose Coral (Fossilized Calcium Carbonate / Silica)
fossil
Crazy Lace Agate
Chalcedony (SiO2) with microcrystalline quartz
sedimentary
Druzy Quartz Geode (with Chalcedony)
Silicon Dioxide (SiO2)
mineral
Clear Quartz crystals on a Matrix base (Geode fragment)
Silicon Dioxide (SiO2)
mineral
Basalt with Vesicular Texture
Aphanitic Mafic Igneous Rock (primarily Plagioclase and Pyroxene)
igneous
Jasper Conglomerate
Polymictic Conglomerate with Jasper and Quartz
sedimentary
Ocean Jasper
Orbicular Jasper (Silicon Dioxide, SiO2)
sedimentary