Quartz (Druzy or Crystalline)
Silicon Dioxide (SiO2)
mineral
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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Geode
Quartz / Chalcedony nodule
sedimentary
Quartz Geode with Calcite
Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Concretion
Septarian concretion (likely containing Calcite or Siderite)
sedimentary
Possible fossilized ammonite or concretion
Indeterminate fossil specimen; possibly an ammonoid mold/cast in iron-rich sedimentary rock
fossil
Veined Pebble (likely a Quartz-Veined Pebble)
Pebble with Mineral Vein (e.g., Quartz Vein in a Chert/Mudstone Pebble)
Sedimentary Rock (possibly conglomerate or breccia with a quartz vein)
Chalcedony with Quartz Crystals
Silicon Dioxide (SiO2)
mineral
Limonite Geode / Ironstone Concretion with Quartz
Limonite with Quartz (FeO(OH)·nH2O + SiO2)
sedimentary
Quartz Geode with Chalcedony
Silicon Dioxide (SiO2) in Geode Form
sedimentary
Geode / Agate Nodule
Silicon Dioxide (SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Iron-rich weathered stone, possibly hematite-rich ironstone
Hematite/goethite-bearing ironstone; predominantly Fe₂O₃ and FeO(OH)
mineral
Chalcedony (specifically Agate or Carnelian)
Silicon Dioxide (SiO2)
mineral
Chert (Arrowhead Fragment)
Chert / Microcrystalline Silicon Dioxide (SiO2)
sedimentary
Concretion
Siderite or Ironstone Concretion
sedimentary
Weathered quartz-rich stone, possibly chalcedony or calcite
Likely microcrystalline quartz (SiO₂) or calcite (CaCO₃); exact identification requires testing
mineral
Iron-rich weathered stone, possibly limonite/goethite
Limonite (mixture of hydrated iron oxides), commonly goethite (α-FeO(OH))
mineral
Septarian Nodule (Galt)
Calcareous concretion / Septarian concretion
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) in Geodic habit
mineral
Concretion (Sandstone)
Sandstone Concretion
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Concretion
Calcareous or ferruginous concretion
sedimentary
Concretion
Septarian Concretion (Clay-Ironstone Nodules)
sedimentary
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Geode
Crystalline Quartz in Sedimentary Matrix (SiO2)
sedimentary
Conglomerate
Conglomerate (Sedimentary Clastic Rock)
sedimentary
Vesicular Basalt (or Scoria)
Extrusive Igneous Rock (Mafic)
igneous
Quartz Geode
Silicon Dioxide (SiO2) within Sedimentary or Igneous host
mineral
Geode (Quartz / Chalcedony Geode)
SiO2 (Silicon Dioxide)
sedimentary
Cannonball Concretion
Calcite-cemented Sandstone Concretion
sedimentary
Limonite Concretion
FeO(OH)·nH2O (Hydrated Iron Oxide)
sedimentary
Sandstone (Graywacke)
Clastic Sedimentary Rock (Lithic Sandstone)
sedimentary
Concretion
Septarian or Siderite Concretion
sedimentary
Amethyst
Silicon Dioxide (SiO2) with iron impurities
gemstone
Limestone (specifically Travertine or Tufa)
Calcium Carbonate (CaCO3)
sedimentary
Geode (Unopened)
Siliceous Geode (SiO2)
sedimentary
Sandstone Concretion
Sedimentary Concretion (Quartz sand bound by mineral cement)
sedimentary
Claystone Concretion
Septarian Concretion (Ironstone-rich)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
mineral