Ironstone Concretion / Limonite Node
Limonite (Hydrated Iron Oxide, FeO(OH)·nH2O) with Goethite/Hematite
Category
Browse sedimentary or metamorphic (low grade) specimens identified by the Rock Identifier community.
Ironstone Concretion / Limonite Node
Limonite (Hydrated Iron Oxide, FeO(OH)·nH2O) with Goethite/Hematite
Conglomerate
Conglomerate Rock (Paraconglomerate)
Ferruginous Sandstone (Gozzanous)
SiO2 (Quartz) with FeO(OH) (Goethite) or Fe2O3 (Hematite) coating
Emerald with Matrix (Emerald in Mica Schist)
Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities
Gneiss
Gneiss (High-grade Metamorphic Rock)
Gneiss
Gneiss (High-grade Metamorphic Rock)
Yellow Agate
Agate (Varietal form of Chalcedony/Quartz, SiO2)
Schist (Kyanite Schist)
Kyanite-Mica Schist (primarily Al2SiO5, KAl2(AlSi3O10)(OH)2, and SiO2)
Conglomerate
Conglomerate (clastic sedimentary rock)
Gneiss
High-grade regional metamorphic rock (Foliated)
Pyrite
Iron Pyrite (FeS2)
Pyrite
Iron Sulfide (FeS2)
Graphite
Graphite (Carbon, C)
Siltstone
Siltstone (primarily SiO2 with Al2O3 and Fe2O3)
Gneiss
Gneiss
Lignite (Brown Coal)
Humic Lignite (Carbonaceous sedimentary rock)
Quartz Mica Schist
Mica-Quartz Schist (Chemical: SiO2 + KAl2(AlSi3O10)(OH)2)
Sandy Ironstone
Ferruginous Sandstone
Conglomerate
Conglomerate (lithified rudite)
Ferruginous Sandstone (Ironstone Nodules)
Ferruginous Sandstone with Limonite/Goethite coating (Fe2O3·H2O)
Ferruginous Sandstone
Clastic sedimentary rock (primarily SiO2 with Fe2O3 cement)
Red Siltstone (or Red Shale)
Clastic Sedimentary Rock (Composition: primarily Quartz, Clay minerals, and Hematite Fe2O3)
Ferruginous Sandstone with Ironstone Concretion
Goethite-rich Sandstone (FeO(OH))
Blue Chalcedony
Silicon Dioxide (SiO2)
Gneiss
Gneiss
Basalt (Greenstone/Trap Rock)
Basalt (dominated by plagioclase feldspar and pyroxene)
Gneiss
Gneiss (Metamorphic rock)
Ruby (Pink to Red Corundum)
Al2O3 (Corundum with Chromium impurities)
Granite Gneiss
Gneiss (High-grade Metamorphic Rock)
Pyrite
Iron Sulfide (FeS2)
Pyrite in Matrix
Iron Sulfide (FeS2)
Amber
Organic gemstone (Succinite is common if from the Baltic)
Milky Quartz Vein in Host Rock
Silicon Dioxide (SiO2)
Green Calcite
Calcium Carbonate (CaCO3)
Kyanite (Purple variety)
Kyanite (Al₂SiO₅)
Prehnite
Prehnite (Ca2Al2Si3O10(OH)2)
Fossilized Wood (with Coal and Limonite)
Petrified Wood (Silicified or Carbonized Flora)
Grey River Stone (Quartz-rich Quartzite/Siltstone)
Quartzite / Meta-siltstone (primarily SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Ironstone with Pyrite
Ferruginous Sandstone (Fe2O3) with minor Sulfide minerals (FeS2)
Emerald in Matrix
Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities
Garnet (Almandine variety)
Almandine Garnet (Fe3Al2(SiO4)3)