Slate
Foliated Metamorphic Rock
Category
Browse rock (likely sedimentary) specimens identified by the Rock Identifier community.
Slate
Foliated Metamorphic Rock
Dyed Agate
Silicon Dioxide (SiO2)
Jasper (specifically Polychrome or Desert Jasper)
Silicon Dioxide (SiO2) with iron oxide and other mineral impurities
Red Sandstone
Clastic sedimentary rock (primarily SiO2 with Fe2O3 iron oxide staining)
Sandstone Concretion
Septarian or Carbonate-cemented Sandstone Concretion
Fossiliferous Limestone
Calcareous biomicrite / Bioclastic limestone
Petoskey Stone (Petrified Favosites)
Favosites (extinct colonial coral), CaCO3 with Silica replacement
Chert (Jasper type)
Microcrystalline Quartz (SiO2)
Chert (and/or Flint)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Bauxite (Pisolitic Bauxite)
Bauxite (mixture of Hydrous Aluminum Oxides)
Chert (Jasper/Mudstone)
Silicon Dioxide (SiO2)
Coquina
Bioclastic Limestone (composed primarily of CaCO3)
Red Sandstone
Clastic sedimentary rock (primarily SiO2 with Fe2O3)
Red Jasper (River Pebble)
Silicon Dioxide (SiO2) with hematite impurities
Jasper
Jasper (Silicon Dioxide, SiO2 plus iron oxide impurities)
Greenstone
Metamorphosed Mafic Igneous Rock
Limestone
Calcium Carbonate (CaCO3)
Common Opal with Host Rock
Opal (Hydrated silica, SiO2·nH2O)
Manganese-coated Sandstone
Clastic sedimentary rock with Manganese Oxide (often Pyrolusite or Psilomelane)
Red Sandstone
Clastic Terrigenous Sedimentary Rock (composed mostly of SiO2 with Fe2O3)
Ferruginous Sandstone
Arenite with Iron-Oxide cement (primarily Fe2O3 • nH2O)
Quartz Geode
Crystalline Silicon Dioxide (SiO2) within a nodule
Sandstone
Sandstone (lithified sand)
Gneiss
Gneiss
Sandstone (with Limonite staining)
Arenite (primarily SiO2 with FeO(OH)·nH2O)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Wonderstone (Banded Rhyolite)
Rhyolite (Silicon Dioxide with Iron Oxide impurities)
Chert (Jasper/Flint variation)
Chert (SiO2)
Chert (Iron-stained)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Sandstone (Quartzose Sandstone)
Arenite (SiO2)
Sandstone
Arenite (SiO2 based clastic rock)
Gneiss
Gneiss
Dalmatian Stone (Dalmatian Jasper)
Peralkaline Quartz-Feldspar Rock with Arfvedsonite
Gneiss (Granitic Gneiss)
Gneiss (composed primarily of Quartz, Feldspar, and Mica/Amphibole)
Quartzite / Sandstone / Chert Mix
Silicon Dioxide (SiO2)
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Bivalve Fossil (Clam/Mollusk)
Class: Bivalvia (Order: Veneroida), Calcium Carbonate (CaCO3)
Ferruginous Sandstone
Clastic sedimentary rock (primarily Quartz with Iron Oxide cement)
Limonite Concretion (Ironstone)
Limonite / Goethite (FeO(OH)·nH2O)
Chert / Jasper
Microcrystalline Quartz (SiO2)
Sandstone (Ferruginous)
Arenite (Fe-rich)
Clear Quartz
Silicon Dioxide (SiO2)