Geode (Quartz)
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.
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Celestite (Celestine)
Strontium sulfate (SrSO4)
mineral
Limonite Concretion (Ironstone)
Limonite (FeO(OH)·nH2O) / Goethite
sedimentary
Quartz (Druzy) in host rock
SiO₂ (Silicon Dioxide) as Quartz, with unspecified host rock components (likely silicates and iron oxides)
Mineral
Agate (specifically a Blue Agate Geode Slice)
Chalcedony (cryptocrystalline variety of Quartz); SiO2
mineral
Sandstone concretion (Ironstone-stained)
Arenite with Limonite/Hematite staining (Silica-based with Iron Oxides)
sedimentary
Calcite Geode
Calcium Carbonate (CaCO3)
mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Blue Lace Agate (Geode/Druzy variant)
Chalcedony (SiO2) with Quartz druzy
mineral
Agate Geode / Nodular Chalcedony
Silicon Dioxide (SiO2) with impurities
mineral
Chert (Arrowhead Preform or Point)
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Quartz on Host Rock
Silicon Dioxide (SiO2)
Mineral Specimen
Blue Chalcedony (likely dyed Agate)
Silicon Dioxide (SiO₂)
mineral
Quartz
Quartz (SiO2 - Silicon Dioxide)
Mineral
Quartz
Silicon Dioxide (SiO₂)
Mineral
Dark-colored Igneous Rock (likely Basalt or Diabase)
Basalt (extrusive igneous) or Diabase (intrusive igneous)
Igneous Rock
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
River Rock / Stream Pebble
Fluvial Clast / Rounded Sedimentary Particle
Sedimentary Rock (possibly composed of various minerals)
Quartz Druze on Matrix
Silicon Dioxide (SiO2)
mineral
Septarian Nodule (Dragon Stone) sphere
Septarian concretion (Calcite, Aragonite, and Limestone)
sedimentary
Quartz
Quartz (SiO2 - Silicon Dioxide)
Mineral
Basalt (Drill Core)
Mafic Volcanic Rock (Basalt)
igneous
Druzy Quartz
Silicon Dioxide (SiO2)
mineral
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Quartz Druzy Geode
Silicon Dioxide (SiO2) - Crystalline Variety
mineral
Quartz Geode
Crystalline Silicon Dioxide (SiO2) within a nodule
sedimentary
Quartz Geode (partially formed)
Silicon Dioxide (SiO2)
mineral
Septarian Nodule
Septarian Concretion
sedimentary
Quartz (Druzy)
Silicon Dioxide (SiO2)
mineral
Sandstone Chert Concretion
Silica-cemented Concretion (primarily SiO2)
sedimentary
Labradorite (likely Black Labradorite or Larvikite)
Labradorite (Na,Ca)(Al,Si)4O8. If a rock, it is typically anorthosite, gabbro, or norite, or a variety of syenite called Larvikite if it is specifically from Larvik, Norway.
Mineral/Igneous Rock
Basalt
Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)
Igneous
Citrine
Quartz (Silicon Dioxide - SiO2)
mineral
Grooved Maun Ball (Maul/Hammerstone-like Concretion)
Calcareous/Ferruginous Concretion in Sandstone Matrix
sedimentary
Septarian Nodule
Septarian Concretion (CaCO3 with Siderite/Limonite streaks)
sedimentary
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Sandstone (Pebble/Conglomerate fragment)
Sandstone (clastic sedimentary rock)
Sedimentary Rock
Geode with Quartz and Chalcedony
Silicon Dioxide (SiO2)
sedimentary
Basalt
Basalt (Composition primarily Plagioclase feldspar, Pyroxene, and Olivine)
igneous
Ferruginous Sandstone
Sandstone, Iron-rich
sedimentary
Gneiss (specifically Granite Gneiss)
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic