Gneiss
Gneiss
Category
Browse sedimentary rock (altered) specimens identified by the Rock Identifier community.
Gneiss
Gneiss
Sandstone (with Iron Siderite Concretion)
Arenite with Ironstone Concretion (FeCO3)
Chert (Chalcedony/Agate)
Microcrystalline Quartz (SiO2)
Red Jasper
Jasper (Silicon Dioxide, SiO2)
Yellow Jasper
Jasper (Silicon Dioxide, SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Chert (Arrowhead/Artifact Fragment)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Jasper (specifically Red or Brecciated Jasper variant)
Jasper (Microcrystalline Quartz - SiO2)
Red Jasper
Jasper (Silicon Dioxide, SiO2)
Riverstone (Quartzite or Siltstone cobble)
Quartzite (primarily SiO2)
Banded Siltstone or Argillite
Siltstone (primarily SiO2 with Al and Fe oxides)
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
Red Jasper (Brecciated Jasper)
SiO2 (Silicon Dioxide) with Ferric Iron inclusions
Sandstone Concretion
Ferruginous Sandstone Concretion
Red Sandstone
Clastic Terrigenous Sedimentary Rock (typically Hematitic Quartz Arenite or Arkose)
Biotite Gneiss
Gneiss (complex mixture including Biotite K(Mg,Fe)3AlSi3O10(F,OH)2 and Quartz/Feldspar)
Chert Breccia
Brecciated Microcrystalline Quartz (SiO2)
Banded Gneiss
Gneiss (High-grade Metamorphic Rock)
Ocherous Sandstone (Ferruginous Sandstone)
Ferruginous Arenite (SiO2 with Fe2O3)
Carnelian
Carnelian (Silicon Dioxide - SiO2)
Carnelian
Carnelian (a variety of Chalcedony); SiO2 (Silicon Dioxide)
Schist (Chlorite or Mica-rich)
Chlorite Schist
Chert / Jasper
Sedimentary Cryptocrystalline Quartz (SiO2)
Ferruginous Sandstone (Gozzan)
Iron-rich clastic sedimentary rock with Limonite/Goethite
Banded Sandstone (Quartzite-rich)
Clastic Sedimentary Rock (SiO2 with Iron Oxide impurities)
Ferruginous Sandstone (Ironstone Conglomerate fragments)
Ferruginous clastic sedimentary rock (SiO2 cemented by Fe2O3)
Conglomerate with Fossilized Shark Teeth
Clastic sedimentary rock (Conglomerate) containing Elasmobranchii remains
Banded Sandstone (River Pebble)
Clastic Sedimentary Rock (primarily Quartzite and Feldspar grains)
Hag Stone
Calcareous sedimentary rock (often Chert, Flint, or Limestone)
Clear Quartz
Silicon Dioxide (SiO2)
Quartz (Milky/Common)
Quartz (Silicon Dioxide, SiO2)
Banded Gneiss (with Quartz Vein)
Gneiss (Metamorphic rock of varying mineralogy)
Gneiss
Gneiss (High-grade Metamorphic Rock)
Limonite (Iron Ore)
Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)
White Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Banded Agate
Cryptocrystalline Quartz (SiO2)
Quartz (Milky or Common Quartz)
Silicon Dioxide (SiO2)
Quartz in Limonite-rich Matrix
Silicon Dioxide (SiO2) with Goethite/Limonite FeO(OH)·nH2O
Quartz with Mica inclusions (likely Schist or Gneiss host)
Silicon Dioxide (SiO2) with Phyllosilicates (KAl2(AlSi3O10)(OH)2)
Agate (specifically Carnelian Agate or Lake Superior style Agate)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Calcite on Limestone (or Fossil)
Calcium Carbonate (CaCO3)
Yellow Jasper
Cryptocrystalline quartz (SiO2) with iron inclusions