Gneiss
Gneissic Metamorphic Rock (Mineral composition: Quartz, Feldspar, Amphibole/Biotite)
Category
Browse sedimentary rock (technically a variety of chalcedony) specimens identified by the Rock Identifier community.
Gneiss
Gneissic Metamorphic Rock (Mineral composition: Quartz, Feldspar, Amphibole/Biotite)
Sandstone (Ferruginous)
Ferruginous Sandstone (SiO2 with iron oxide cement)
Quartz (Milky/Bull Quartz)
Silicon Dioxide (SiO2)
River Stone (Granitic Gneiss)
Foliated Granitic Gneiss
Red Granite
Phaneritic Plutonic Felsic Rock (rich in Potassium Feldspar)
Pink Granite (Alkali Feldspar Granite)
Phaneritic Plutonic Felsic Rock (SiO2, KAlSi3O8, NaAlSi3O8)
Sandstone
Arenite (variable SiO2 composition)
Sandstone
Arenite (SiO2 based)
Flagstone (Sandstone)
Clastic Sedimentary Rock (composed of quartz and feldspar)
Quartz / Common Opal
Silicon Dioxide (SiO2)
Sandstone (Ferruginous)
Arenite with Iron oxide staining (SiO2 with Fe2O3)
Laterite
Laterite (primarily composed of hydrated oxides of iron and aluminum)
Quartz Geode
Silicon Dioxide (SiO₂)
Limestone (Fossiliferous)
Calcium Carbonate (CaCO3) - Bioclastic Limestone
Serpentine
Serpentinite (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4
Banded Agate (with possible Chalcedony layers)
Silicon dioxide (SiO2)
Sandstone
Arenite
Sandstone
Arenite (primarily Quartz, SiO2)
Basalt
Basalt (Aphanitic-to-porphyritic mafic volcanic rock)
Limestone
Calcium Carbonate (CaCO3)
Hematite
Iron(III) oxide (Fe2O3)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
Rose Quartz
Silicon Dioxide (SiO2)
Chert (Jasper/Iron-stained Quartzite)
Silicon Dioxide (SiO2)
Carnelian Agate
Silicon Dioxide (SiO2) with iron oxide impurities
Coal (Bituminous or Anthracite)
Carbonaceous sedimentary rock (primarily Carbon, C)
Sandstone (Ferruginous)
Arenite (Fe-bearing Clastic Sedimentary Rock)
Sandstone (Greywacke)
Arenite / Wacke (Mainly SiO2 with various lithic fragments)
Yellow Apatite Sphere (Polished)
Fluorapatite / Ca5(PO4)3F
Quartz Geode (Cracked Open)
Quartz (Silicon Dioxide - SiO2)
Ironstone (with possible Hematite/Limonite coating)
Ironstone (Fe-rich sedimentary rock)
Common Green Opal
Hydrated amorphous silicon dioxide (SiO2·nH2O)
Mixed Tumbled Stones (Mostly Agate, Jasper, and Quartz)
Silicon Dioxide (SiO2)
Granite
Phaneritic Plutonic Igneous Rock (primarily composed of quartz, alkali feldspar, and plagioclase)
Vesicular Basalt (River Pebble)
Vesicular Basalt
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Chert (Jasper/Flint variety)
Silicon Dioxide (SiO2)
Coquina Limestone (Fossiliferous Limestone)
Calcareous bioclastic sedimentary rock (CaCO3)
Dragon Stone
Ohko Stone (Argillaceous sedimentary rock)
Bituminous Coal
Bituminous coal (Organic Sedimentary Rock)
Jasper Conglomerate (Puddingstone)
Jasper Conglomerate (Siliceous Sedimentary Rock)
Sandstone (Banded)
Clastic Sedimentary Rock (primarily SiO2)