Gneiss
Gneiss
Category
Browse sedimentary rock (technically a microcrystalline quartz mineral aggregate) specimens identified by the Rock Identifier community.
Gneiss
Gneiss
Gneiss (specifically Granitic Gneiss)
Gneiss (composed primarily of Quartz, Feldspar, and Biotite/Amphibole)
Banded Gneiss
Gneiss (Metamorphic Rock)
Chert (and/or Flint)
Microcrystalline Quartz (SiO2)
Chert (Field Stone/Jasper variety)
Microcrystalline Quartz (SiO2)
Yellow Quartzite (River Pebble)
Quartzite (mainly SiO2)
Wishing Stone with Quartz Veins
Quartzite or Quartz-veined Metamorphic Rock (composed mainly of SiO2)
Chert (Flint)
Chert (predominantly SiO₂ - silicon dioxide)
Brecciated Jasper
Silicon Dioxide (SiO2) with varying mineral inclusions (Iron Oxide, Hematite, Clay)
Carnelian Agate
Silicon Dioxide (SiO2) - variety of Chalcedony
Chert (specifically Jasper/Carnelian variety)
Microcrystalline quartz (SiO2)
Ironstone Concretion / Goethite Nodules
Ironstone (composed primarily of Goethite FeO(OH) and Limonite)
Quartz Mica Schist
Mica-Quartz Schist (Chemical: SiO2 + KAl2(AlSi3O10)(OH)2)
Quartz Druze on Matrix
Silicon Dioxide (SiO2)
Red Jasper
Silicon dioxide (SiO2) with iron inclusions
Sandstone
Arenite (often composed of Quartz, SiO2)
Sandstone (River Pebble)
Arenite (primarily SiO2)
Ocean Jasper (Orbicular Jasper)
Silicon Dioxide (SiO2) - Variety of Chalcedony/Quartz
Wishing Stone (Basalt or Mudstone with Quartz/Calcite Veins)
Hydrothermally veined Basalt (SiO2/CaCO3 intrusions)
Granite
Granite (a plutonic igneous rock composed primarily of quartz and feldspar)
Jasper
Cryptocrystalline Quartz (SiO2)
Sandstone
Arenite
Basalt
Mafic Igneous Rock (composed primarily of plagioclase, pyroxene, and olivine)
Granite
Granite (a phaneritic intrusive igneous rock)
Fancy Jasper
Silicon Dioxide (SiO₂)
Banded Gneiss
Gneiss (High-grade metamorphic rock)
Herkimer Diamond
Quartz (Silicon Dioxide, SiO2)
Jasper with Chert
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Sandstone
Arenite (primarily Quartz, SiO2)
Quartz
Silicon dioxide (SiO2)
Geode (unopened)
Calcedony-lined Geode (SiO2)
Quartzite
Quartzite (primarily SiO2)
Limonite (after Pyrite Pseudomorph)
Limonite (Hydrated Iron Oxide Mixture, FeO(OH)·nH2O)
Chert (or Flint)
Chert (microcrystalline or cryptocrystalline quartz, SiO2)
Chert (Jasper/Common Opal mix)
Microcrystalline Quartz (SiO2)
Flint Nodule
Microcrystalline Quartz (SiO2)
Sandstone (Ferruginous)
Arenite with Iron Oxide (Fe2O3) cement
Quartzite Pebbler
Quartzite (mainly SiO2)
Quartz
Quartz (SiO₂)
Carnelian
SiO2 (Microcrystalline Quartz / Chalcedony)
Quartzite Pebble
Quartzite (SiO2)
Quartz Pebble (Chalcedony/Agate variety)
Silicon Dioxide (SiO2)