Ironstone Concretion / Limonite-stained Siltstone
Ironstone (primarily Limonite FeO(OH)·nH2O and Siltstone)
Category
Browse sedimentary rock (specifically a clastic sedimentary rock formed into a cobble) specimens identified by the Rock Identifier community.
Ironstone Concretion / Limonite-stained Siltstone
Ironstone (primarily Limonite FeO(OH)·nH2O and Siltstone)
Gneiss
Gneiss
Milky Quartz
Silicon Dioxide (SiO2)
Hag Stone (Banded Chert or Limestone with Borehole)
Microcrystalline Quartz (Chert) or Calciferous Siltstone (CaCO3/SiO2)
Sandstone (Quartzose)
Arenite (primarily SiO2)
Hag Stone
Calcareous sedimentary rock (often Chert, Flint, or Limestone)
Jasper (likely Brecciated or Multi-colored)
Jasper (SiO2)
Chert (Tripolitic Chert / Flint Nodules)
Microcrystalline Quartz (SiO2)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Bivalve Fossil (Internal Mold/Steinkern)
Class Bivalvia (Fossilized Mold)
Sand Dollar Fossil (Echinoidea)
Class Echinoidea (likely order Clypeasteroida), CaCO3 (Calcite)
Chert (Septarian Nodules / Weathered Silex)
Microcrystalline Quartz (SiO2)
Turquoise
Hydrous phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)
Quartz
Quartz (Silicon Dioxide, SiO2)
Sandstone
Arenite (composed primarily of SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Pink Granite
Phaneritic Felsic Igneous Rock (Granite)
Halite (Rock Salt)
Halite (NaCl)
Halite (Rock Salt)
Halite (Sodium Chloride, NaCl)
Garnet Schist
Almandine Garnet-Mica Schist (X₃Y₂(SiO₄)₃)
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Pink Granite
Phaneritic Felsic Intrusive Igneous Rock
Gneiss
Gneiss
Coquina
Biogenic Limestone (CaCO3)
Sandstone (Pebble)
Sandstone (arenite, arkose, wacke depending on composition)
Gastropod Steinkern (Fossilized Snail Cast)
Phylum Mollusca, Class Gastropoda (Commonly CaCO3 or SiO2 after replacement)
Honey Calcite
Calcite (Calcium Carbonate, CaCO3)
Coquina Jasper
Fossiliferous Chalcedony (SiO2)
Chert (Common Opal/Chalcedony mixture)
Silicon Dioxide (SiO2)
Clear Quartz
Silicon Dioxide (SiO2)
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
Coral Fossil (Favosites type)
Phylum Cnidaria, Class Anthozoa (often CaCO3 - Calcium Carbonate)
Carnelian Agate
Carnelian (SiO2 with iron oxide impurities)
Red Quartz (Carnelian/Red Jasper Agate)
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Gneiss
High-grade metamorphic rock (Gneiss)
Chert Nodule (River Cobble)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
Biotite (Mica)
Biotite group (K(Mg,Fe)3AlSi3O10(F,OH)2)
Chert (Black Chert/Flint)
Chert (Silicon Dioxide, SiO2)
Travertine (Calcareous Tufa)
Calcium Carbonate (CaCO3)
Gneiss (Metamorphic Rock)
Gneiss