Basalt
Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)
Igneous
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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Quartz Geode
Silicon Dioxide (SiO2)
mineral
Celestite (Celestine)
Strontium sulfate (SrSO4)
mineral
Chert Nodule / Flint
Microcrystalline Quartz (SiO2)
sedimentary
Quartz / Common Agate
Silicon Dioxide (SiO2)
mineral
Calcite Geode
Calcium Carbonate (CaCO3)
mineral
Fossiliferous limestone
Bioclastic carbonate rock, chiefly calcite (CaCO₃)
sedimentary
Ironstone Concretion (Limonite/Goethite)
Iron-rich sedimentary rock (FeOx)
sedimentary
Basalt
Basalt (Composition primarily Plagioclase feldspar, Pyroxene, and Olivine)
igneous
Quartz Geode
Quartz (Silicon Dioxide, SiO2)
Mineral
Geode (unopened)
Chert / Chalcedony Geode (SiO2)
sedimentary
Basalt
Fine-grained mafic volcanic rock, chiefly plagioclase feldspar, pyroxene, and commonly olivine
igneous
Quartz Geode
Silicon Dioxide (SiO2) in a Geode body
sedimentary or igneous (host environment)
Blue Lace Agate (Geode/Druzy variant)
Chalcedony (SiO2) with Quartz druzy
mineral
Quartz Druzy (Geode Fragment)
Silicon Dioxide (SiO2)
mineral
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Ironstone Nodules (Limonite/Hematite)
Goethite/Hematite mix (FeO(OH)/Fe2O3)
sedimentary
Moqui Marble
Hematite Concretion (Iron Oxide Concretion)
sedimentary
Agate Geode Slice
Silicon Dioxide (SiO2) with trace elements
sedimentary
Ocean Jasper
Spherulitic Chalcedony (SiO2)
sedimentary
Limonite Concretion (Ironstone)
Limonite (FeO(OH)·nH2O) / Goethite
sedimentary
Polished Agate (Green and White Chalcedony)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
mineral
Clear Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Quartz Geode in Chert/Limestone Matrix
Silicon Dioxide (SiO2) within Sedimentary Host Rock
sedimentary
Weathered iron-rich rock, possibly basalt or limonite-bearing sandstone
Undetermined; likely Fe-oxide-stained basalt or ferruginous sandstone (hematite/goethite-bearing)
igneous
Quartz Geode Pebble
Silicon Dioxide (SiO2)
sedimentary
Quartz Druzy Geode Fragment
Silicon Dioxide (SiO2)
mineral
Druzy Quartz Geode (Partially Open)
Silicon Dioxide (SiO2) within Sedimentary Host Rock
sedimentary
Quartz Druzy (on Matrix)
Silicon Dioxide (SiO2)
mineral
Amethyst (Tumbled)
Amethyst (SiO2 with iron impurities)
mineral
Quartz Geode (Druzy Quartz)
Silicon Dioxide (SiO2)
mineral
Quartz Geode (partially filled/solid)
Silicon Dioxide (SiO2)
sedimentary
Gneiss (specifically Pink Gneiss)
Gneiss (high-grade regional metamorphic rock)
metamorphic
Quartz Geode
Crystalline Silicon Dioxide (SiO2) in Geode
mineral
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Quartz Geode (Druzy Quartz)
Silicon Dioxide (SiO2)
mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Limonite (Ironstone Concretion)
Limonite (FeO(OH)·nH2O)
sedimentary
Chert Concretion (Flint)
Silicon Dioxide (SiO2)
sedimentary
Gneiss (specifically Biotite Gneiss)
Gneiss (high-grade metamorphic rock primarily composed of Silicates)
metamorphic