Ferruginous Siltstone or Mudstone
Ferruginous Siltstone / Goethitic Sandstone
sedimentary
Category
Sedimentary (Secondary Mineral Formation)
Browse sedimentary (secondary mineral formation) specimens identified by the Rock Identifier community.
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Specular Hematite (Specularite)
Iron Oxide (Fe2O3)
mineral
Iron-rich concretion or weathered ironstone
Limonite/goethite-rich ironstone; commonly hydrated iron oxides (FeO(OH)·nH₂O)
sedimentary
Banded Agate
Cryptocrystalline Quartz (SiO2) with iron oxide inclusions
mineral
Sandstone / Quartzite
Sedimentary quartz arenite
sedimentary
Quartz with Iron Oxide Inclusions
SiO2
mineral
Milky calcite
Calcite (calcium carbonate, CaCO₃)
mineral
Small tan rock fragment
Indeterminate; possibly quartz-rich sandstone or iron-stained quartz
mineral
Milky Quartz
SiO2 (Silicon Dioxide)
mineral
Chert with Quartz Veining
Silicon Dioxide (SiO2)
sedimentary
Hematite Beads
Iron Oxide (Fe2O3)
mineral
Red Jasper
Silicon Dioxide (SiO2) with Iron inclusions
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Chert (Brecciated or Veined)
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone (with Quartz veining)
Arenite (primarily SiO2)
sedimentary
Iron-rich weathered rock, possibly ironstone
Ironstone (composition uncertain; likely iron oxides such as goethite and limonite)
sedimentary
Quartz Geode (with Agate banding)
Silicon Dioxide (SiO2)
Sedimentary or Igneous (secondary formation)
Iron-rich rock or Concretion
Ironstone or Limonite concretion
sedimentary
Quartz (Citrine or Smoky variety)
Silicon Dioxide (SiO2)
mineral
Geode with Quartz Crystals
SiO2 (Silicon Dioxide) in a geode formation
Sedimentary/Igneous (depending on host rock)
Hematite
Iron(III) oxide (Fe2O3)
mineral
Fossiliferous limestone
Bioclastic carbonate rock, chiefly calcite (CaCO₃), with fossil shells/coral fragments
sedimentary
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Unidentified small rock fragment
Likely quartz-rich material; exact identification is indeterminate from the image
mineral
Unidentified gray-brown stone
Likely fine-grained quartz–feldspar rock; exact identification is not possible from this close, blurred image
mineral
Iron-stained weathered stone (tentative)
Undetermined; possibly weathered iron-rich basalt or concretion
mineral
Feldspar (specifically Orthoclase or Plagioclase)
Potassium Aluminum Silicate (KAlSi3O8) or Sodium/Calcium Aluminum Silicate
mineral
Shale with Iron Staining
Fissile Argillaceous Sedimentary Rock
sedimentary
Quartz
Silicon Dioxide (SiO2)
mineral
Limestone with Iron Inclusions
Calcium Carbonate (CaCO3) with Hematite/Limonite
sedimentary
Hematite
Iron(III) oxide (Fe2O3)
mineral
Basalt with Quartz Veining
Basalt (Mafic Extrusive Igneous Rock) with SiO2 (Silicon Dioxide) veins
igneous
Zebra Stone
Siltstone (Argillaceous Siltstone)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Blue Apatite
Apatite (Ca5(PO4)3(F,Cl,OH))
mineral
Sandstone with Iron Staining
Arenite with Limonite/Hematite inclusions (SiO2 + Fe2O3/FeO(OH))
sedimentary
Breciated Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Geode (Chert or Quartz Nodule)
Silicon Dioxide (SiO2)
sedimentary
Quartz
Silicon Dioxide (SiO2)
Mineral
Mica-rich schist
Mica schist, likely muscovite–biotite schist with quartz
metamorphic
Chert with Iron Oxide Staining
Microcrystalline Quartz (SiO2) with Limonite/Goethite staining
sedimentary
Blue calcite (likely)
Calcite, calcium carbonate (CaCO₃)
mineral