Weathered limestone or calcitic cave deposit
Calcite (CaCO₃), likely porous limestone/travertine
sedimentary
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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Chert (or Flint)
SiO2 (predominantly microcrystalline quartz)
Sedimentary
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Ironstone Concretion (Moqui Marble type)
Ironstone Concretion (Fe2O3 with SiO2 core)
sedimentary
Amethyst (Geode/Druzy)
Silicon Dioxide (SiO2) with iron impurities
mineral
Quartz Geode
Silicon Dioxide (SiO2)
sedimentary
Quartz Geode (Unbroken)
Silicon Dioxide (SiO2)
sedimentary
Basalt
Basalt
igneous
Geode (Unopened)
Silicon Dioxide (SiO2) in sedimentary vugs
sedimentary
Geode (unopened)
Calcedony-lined Geode (SiO2)
sedimentary
Greenish Metamorphic Rock (likely containing epidote or chlorite)
Metamorphic rock, possibly epidosite or greenstone
Metamorphic
Weathered iron-rich rock or concretion
Likely limonite/goethite-bearing concretion; exact identification requires testing
sedimentary
Chert (or Flint)
Chert (cryptocrystalline quartz), SiO2
Sedimentary
Pebble (river rock/beach pebble)
Pebble (clast size class)
Sedimentary Rock
Quartz Geode / Druzy Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone with Ironstone Concretion
Arenite with Ferruginous Cement
sedimentary
Ironstone Concretion
Siderite or Hematite Concretion (FeCO3 or Fe2O3)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Basalt (Vesicular/Scoria)
Basalt (Extrusive Mafic Rock)
igneous
Quartz Geode with Calcite/Siderite
Crystalline Silicon Dioxide (SiO2) with Carbonate inclusions
mineral
Basalt
Mafic volcanic rock
igneous
Quartz Geode (partially formed)
Silicon Dioxide (SiO2)
mineral
Fluorite Geode
Calcium Fluoride (CaF2)
mineral
Citrine
Quartz (Silicon Dioxide - SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Amethyst (Raw Cluster)
Silicon Dioxide with iron impurities (SiO2)
mineral
Aragonite / Calcite Geode
Calcium Carbonate (CaCO3)
mineral
Painted Rock / Geode Specimen
Silicon Dioxide with artificial pigment coating
mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Limonite / Ironstone Concretion
Hydrated Iron Oxide (FeO(OH)%C2%B7nH2O)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) in a Secondary Sedimentary/Volcanic cavity
mineral
Sandstone (with secondary weathering/concretion)
Arenite (composed primarily of Quartz, SiO2)
sedimentary
Septarian Nodule
Septarian Concretion (CaCO3 with Calcite and Aragonite)
sedimentary
Quartz Geode
Crystalline Silicon Dioxide (SiO2) in Geode form
sedimentary
Ironstone Concretion (Nutstone)
Ironstone (with High Limonite/Hematite Content)
sedimentary
Agate Geode
Silicon Dioxide (SiO2) - variety Chalcedony/Quartz
sedimentary
Fossilized Nut / Coprolite / Concretion
Trace Fossil / Permineralized Plant Material
fossil
Ironstone Concretion (Boji Stone/Moqui Marble type)
Goethite/Hematite-encrusted Sandstone Concretion
sedimentary
Pink Granite
Phaneritic Quartz-Feldspar Plutonic Rock
igneous
Quartz Geodes and Crystal Clusters
Silicon Dioxide (SiO2)
mineral
Bumblebee Jasper
Fibrous Calcite and Quartz with Volcanic Matter (CaCO3 / SiO2)
mineral