Gneiss
Metamorphic Gneiss
Category
Browse mineral and sedimentary specimens identified by the Rock Identifier community.
Gneiss
Metamorphic Gneiss
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Conglomerate
Conglomerate (clastic sedimentary rock)
Garnet (likely Almandine)
Almandine Garnet, Fe3Al2(SiO4)3
Common Opal
Hydrated amorphous form of silica (SiO2·nH2O)
Sandstone
Arenite (SiO2 based)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Sandstone with Liesegang Rings
Clastic Sedimentary Rock with Iron Oxide Precipitates (SiO2 + Fe2O3)
Ferruginous Sandstone
Arenite with Iron-Oxide Cement (SiO2 with Fe2O3/FeO(OH))
Gneiss
Gneiss
Druzy Quartz on Limestone
Silicon Dioxide (SiO2)
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Sandstone (lithic wake/graywacke variety)
Arenite/Greywacke (SiO2 with lithic fragments)
Greywacke (River Slikenside)
Greywacke (Lithic Sandstone)
Green Fluorite
Calcium Fluoride (CaF2)
Black Opal
Hydrated Silica (SiO2·nH2O)
Green Calcite
Calcite (CaCO3)
Sandstone
Arenite
Sandstone
Arenite (SiO2 primarily)
Sandstone
Arenite (composed primarily of SiO2)
Red Jasper (Chert)
Silicon Dioxide (SiO2) with iron oxide inclusions
Quartz Geode
Silicon Dioxide (SiO2)
Ironstone concretion
Siderite or Limonite concretion (FeCO3 or FeO(OH)·nH2O)
Sandstone Concretion
Arenaceous concretion (primarily SiO2 with Fe2O3 staining)
Ironstone Concretion
Siderite or Hematite Concretion (FeCO3 or Fe2O3)
Red Jasper
Jasper (Silicon Dioxide, SiO2)
Bivalve Fossil (Internal Mold/Steinkern)
Class Bivalvia (Fossilized Mold)
Geode
Crystalline Quartz (SiO2) within a nodule
Sandstone (Iron-stained)
Clastic sedimentary rock (SiO2 with Fe2O3 staining)
Sandstone Concretion
Sandstone (Sedimentary Rock) with silica or calcite cement
Sandstone (River Cobble)
Clastic Sedimentary Rock (primarily Quartz with Feldspar)
Yellow Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Jasper
Silicon dioxide (SiO2)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with iron oxide Fe2O3 cement)
Carnelian
Chalcedony (cryptocrystalline quartz), SiO2 (Silicon Dioxide)
Gneiss (with Quartzite and Biotite)
Gneiss containing SiO2 (Quartz), K(Mg,Fe)3AlSi3O10(OH)2 (Biotite), and (K,Na,Ca)AlSi3O8 (Feldspar)
Pyrite on Limestone
Iron Disulfide (FeS2) in Calcium Carbonate (CaCO3) matrix
River Rock (Mossy)
Stream-rounded Clast (likely Siltstone or Sandstone with bryophytes)
Red Sandstone
Arenite (with Iron Oxide)