Limonite Concretion (Ironstone)
Limonite / Goethite (FeO(OH)·nH2O)
Category
Browse sedimentary (secondary mineral formation) specimens identified by the Rock Identifier community.
Limonite Concretion (Ironstone)
Limonite / Goethite (FeO(OH)·nH2O)
Sandstone
Arenite (primarily SiO2)
Shale creek bed
Shale (fine-grained clastic sedimentary rock)
Sandstone
Arenite (composed primarily of SiO2)
Sandstone (Quartz-rich)
Arenite (composed primarily of SiO2)
Sandstone
Arenite (SiO2 based with various mineral cements)
Rhodonite
Manganese Silicate (Mn,Fe,Mg,Ca)SiO3
Pyrite
Iron Disulfide (FeS2)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)
Yellow Calcite
Calcium Carbonate (CaCO3)
Blue Chalcedony
Silicon Dioxide (SiO2)
Fluorite
Calcium Fluoride (CaF2)
Orange Calcite
Calcium Carbonate (CaCO3)
Satin Spar Selenite
Calcium Sulfate Dihydrate (CaSO4·2H2O)
Quartz Geode
Crystalline Silicon Dioxide (SiO2) within a nodule
Dalmation Stone (Dalmation Jasper)
Peralkaline rock (primarily Feldspar and Quartz with Arfvedsonite spots)
Sandstone with Iron Oxide (Limonite/Hematite)
Ferruginous Sandstone (SiO2 with FeO(OH)·nH2O)
Sandstone (Red)
Arenite (Fe2O3 heavy)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Sandstone (likely Arkosic or Quartzose)
Arenite (SiO2 based with mineral inclusions)
Sandstone (Ferruginous)
Arenite (Fe-rich)
Sandstone
Arenite
Bauxite
Bauxite (Al(OH)3 mixed with Fe2O3 and clay minerals)
Geode (Unopened)
Silica-rich Concretion (primarily SiO2)
Ironstone Concretion (Iron-rich Mudstone)
Siderite / Geothite concretion (FeCO3 / FeO(OH))
Amethyst Geode
Amethyst (Silicon Dioxide), Formula: SiO2
Sandstone (Quartzite-rich)
Clastic Sedimentary Rock (primarily SiO2)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Schist
Chlorite/Mica Schist
Gneiss
Gneiss
Serpentinite
Serpentinite (composed primarily of serpentine-group minerals like antigorite, chrysotile, and lizardite; chemical formula varies but generally Mg3Si2O5(OH)4)
Moss Agate
Moss Agate (a variety of Chalcedony, SiO ₂)
Blue Chalcedony
Chalcedony (SiO2)
Moqui Marble (Concretion)
Iron Oxide Concretion (Hematite-cemented Sandstone)
Gneiss
Gneiss
Porphyritic Rhyolite (Red Porphyry)
Porphyritic Rhyolite (Felsic volcanic rock)
Aquamarine with Sunstone
Aquamarine (Be3Al2Si6O18), Sunstone (Na,Ca)Al(Si,Al)Si2O8
Sandstone (with minor quartz and possible clay components)
Clastic Sedimentary Rock (SiO2 dominated)
Sandstone (Quartzite-rich)
Clastic sedimentary rock (primarily SiO2)
Gneiss
Gneiss (High-grade Metamorphic Rock)
Baroque Pearl
Calcium Carbonate (Aragonite or Calcite) and Conchiolin