Quartz-rich crystal aggregate
Quartz (SiO₂), possibly druzy quartz with iron-oxide staining
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.
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Liesegang Banded Sandstone (Concretion / Weathered Pebble)
Sandstone showing Liesegang rings / Weathering rind (SiO2 with iron oxides)
sedimentary
Septarian Nodule
Septarian Concretion (CaCO3 with Siderite/Limonite streaks)
sedimentary
Sandstone (Ferruginous)
Arenite (with iron oxide cement, Fe2O3)
sedimentary
Milky Quartz Nodule / Geode precursor
Silicon Dioxide (SiO2)
mineral
Geode with Quartz Crystals
SiO2 (Silicon Dioxide) in a geode formation
Sedimentary/Igneous (depending on host rock)
Polished purple quartz (likely amethyst)
Amethyst, a purple variety of quartz (SiO₂), possibly with iron-oxide staining or matrix
mineral
Porous limestone (likely reef or shell limestone)
Calcium-carbonate rock, predominantly calcite (CaCO₃); possibly bioclastic limestone or coquina
sedimentary
Quartz Druzy / Quartz Crystal Cluster
Silicon Dioxide (SiO2)
mineral
Railway Ballast (Crushed Traprock / Basalt with Iron Oxide Staining)
Mafic Volcanic Rock (Basalt / Diabase with Fe2O3.nH2O limonite coatings)
igneous
Iron-rich sedimentary rock, likely banded iron formation fragment
Banded iron formation (BIF), composed chiefly of hematite/magnetite and chert
sedimentary
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Geode with Quartz and Chalcedony
Silicon Dioxide (SiO2)
sedimentary
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide and organic impurities
sedimentary
Quartz-lined agate/geode slice
Microcrystalline quartz (chalcedony, SiO₂) with drusy quartz; possibly calcite inclusions
mineral
Grooved Maun Ball (Maul/Hammerstone-like Concretion)
Calcareous/Ferruginous Concretion in Sandstone Matrix
sedimentary
Celestite (Celestine)
Strontium sulfate (SrSO4)
mineral
Chert
Silicon dioxide (SiO2)
Sedimentary
Quartz on Host Rock
Silicon Dioxide (SiO2)
Mineral Specimen
Quartz Crystal Geode / Druzy Cluster
Silicon Dioxide (SiO2)
mineral
Limestone (specifically Fossiliferous Limestone)
Calcium Carbonate (CaCO3)
sedimentary
Quartz Geode (River Cobble)
Silicon Dioxide (SiO2)
mineral
Diabase
Diabase (also known as Dolerite)
igneous
Amethyst Geode
Silicon Dioxide with trace inclusions of Iron (SiO2)
mineral
Pink Amethyst (or Pink Quartz)
Silicon Dioxide (SiO2) with trace inclusions
gemstone
Amethyst and Smoky Quartz (Tumbled)
Silicon Dioxide (SiO2) with trace impurities iron (Amethyst) and aluminum/radiation (Smoky Quartz)
mineral
Conglomerate
Polymictic Conglomerate
sedimentary
Turtle Stone / Septarian Nodule (Water-worn)
Septarian Concretion
sedimentary
Quartz geode
Silica geode; predominantly microcrystalline and crystalline quartz (SiO₂), possibly with chalcedony
mineral
Chert Nodule / Flint
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone Concretion
Sedimentary Concretion (SiO2 or CaCO3 cemented)
sedimentary
Moqui Marble
Hematite-Goethite Concretion
mineral
Quartz Geode
Quartz (Silicon Dioxide, SiO2)
Mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Red Quartz (Druzy)
Silicon Dioxide (SiO2) with Hematite inclusions
mineral
Basalt (Vesicular)
Basalt (Mafic Extrusive Igneous Rock)
igneous
Likely ironstone concretion or weathered iron-rich rock
Goethite/hematite-bearing limonite (FeO(OH)·nH₂O / Fe₂O₃)
mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Chert Nodule / Ironstone Concretion
Microcrystalline Quartz (SiO2) with Iron Oxides
sedimentary
Basalt
Basalt
igneous
Limonite Concretion
Limonite (FeO·nH2O)
mineral
Ironstone Concretion
Ferruginous Concretion
sedimentary