![Limonite Geode (Ironstone Concretion) (Limonite [FeO(OH)·nH2O] with possible Quartz or Calcite interior) — sedimentary](https://media.rock.id/23e3b366-c658-41d4-99f3-53fdaa23a555-thumbnail.jpg)
Limonite Geode (Ironstone Concretion)
Limonite [FeO(OH)·nH2O] with possible Quartz or Calcite interior
sedimentary
Category
Sedimentary
Browse sedimentary specimens identified by the Rock Identifier community.
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Knightia Fossil in Limestone
Knightia eocaena in micritic limestone
sedimentary
Puddingstone (Gowganda)
Gowganda Formation Conglomerate
sedimentary
Small weathered mineral/rock fragment
Indeterminate; possibly quartz-bearing feldspathic rock or calcite-rich specimen
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Red Jasper and Hematite
Silicon Dioxide (SiO2) and Iron Oxide (Fe2O3)
mineral
Red Jasper or Ironstone concretion
SiO2 or Fe2O3
sedimentary or mineral
Aragonite Star Cluster (Cross-section)
Aragonite (Calcium Carbonate, CaCO3)
mineral
Blue Calcite
Calcium Carbonate (CaCO3)
mineral
Magnetite (Iron Ore)
Iron(II,III) oxide (Fe3O4)
mineral
Brown Jasper (Tumbled)
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Fluorite, Turquoise, and Calcite set
Calcium Fluoride (CaF2), Hydrous Phosphate of Copper and Aluminum (CuAl6(PO4)4(OH)8·4H2O), Calcium Carbonate (CaCO3)
mineral
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Quartz Geode
Silicon Dioxide (SiO2) in Host Rock
sedimentary
Jasper (Iron-rich)
Silicon Dioxide (SiO2) with Fe2O3 (Hematite) impurities
sedimentary
Red Jasper (Polished)
Jasper (Iron-rich Microcrystalline Quartz, SiO2)
sedimentary
Geode (Chert or Quartz Nodule)
Silicon Dioxide (SiO2)
sedimentary
Chert (Chert Nodule with Chalky Cortex)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Halite (Rock Salt)
Halite (Sodium Chloride, NaCl)
mineral
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Orange Calcite (Cleavage Rhomb)
Calcite (Calcium Carbonate, CaCO3)
mineral
Manganese Ore (Psilomelane/Pyrolusite)
Psilomelane ((Ba,H2O)2Mn5O10) and Pyrolusite (MnO2)
Mineral
Yellow Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Green Opal
Hydrated Silica (SiO2·nH2O)
mineraloid
Red sandstone
Quartz-rich sandstone, commonly ferruginous (Fe-oxide stained)
sedimentary
Fossilized Shell Fragment
Invertebrate marine fossil, likely calcium carbonate replacement
fossil
Quartz-veined Sandstone Pebble
Quartzite-veined Arenite
sedimentary
Devil's Toenail
Gryphaea (extinct genus of foam oysters, typically composed of Calcite CaCO3)
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Fossiliferous Limestone with Brachiopod
Phylum Brachiopoda in calcitic matrix
sedimentary
Lepidodendron Fossil in Sandstone
Lepidodendron (Lycophytina, Lepidodendrales)
sedimentary
Bivalve Seashell Fossil
Class Bivalvia
fossil
Pebble (likely Quartz or Chert)
SiO₂ (Silicon Dioxide) - referring to the likely main mineral composition, Quartz. If it's chert, the scientific name remains SiO₂ with a microcrystalline structure.
Sedimentary Rock
Sandstone / Weathered Quartzite
Sandstone (Quartz Arenite)
sedimentary
Sandstone
Arenite (Sedimentary rock composed of sand-sized grains, primarily SiO2)
sedimentary
Ironstone Pebble
Sedimentary Ironstone (Hematite/Limonite-bearing)
sedimentary
Rounded quartz-rich sandstone cobble
Quartz arenite (sandstone), likely iron-stained
sedimentary
Coal
Bituminous Coal / Anthracite
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) within a sedimentary or igneous host
sedimentary
Coquina / Shelly Sandstone
Calcareous Sandstone / Coquina
sedimentary
Banded gneiss
Gneiss, commonly quartz–feldspar–mica gneiss
metamorphic