Tree Agate
Dendritic Agate (Silicon Dioxide, SiO2)
Category
Browse sedimentary or metamorphic (base substrate) specimens identified by the Rock Identifier community.
Tree Agate
Dendritic Agate (Silicon Dioxide, SiO2)
Pink Granite
Phaneritic Plutonic Felsic Igneous Rock (Granite)
Limestone
Sedimentary rock composed primarily of Calcium Carbonate (CaCO3)
Schist
Schist (Foliated Metamorphic Rock)
Garnet Schist
Almandine-mica schist
Chert (with Quartz veins)
Chert (Microcrystalline Silicon Dioxide, SiO2)
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
Coquina
Biogenic Limestone (Coquina)
Chert (specifically White Chert or Novaculite)
Silicon Dioxide (SiO₂)
Coquina
Biogenic Limestone (Calcitic shells)
Chert (specifically Tan Chert)
Chert (SiO2)
Chert (Iron-stained)
Chert (SiO2 - Silicon Dioxide)
Chert (varieties include Jasper or Flint)
Chert (Microcrystalline Silica, formula: SiO2)
Chert (Flint)
Silicon Dioxide (SiO2)
River Siltstone / Mudstone Pebble
Siltstone (composed of mixed silicate and carbonate minerals)
Brecciated Chert
Brecciated Chert (Microcrystalline Quartz, SiO2)
Chert / Quartz Pebble
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Slate
Slate (foliated metamorphic rock)
Sandstone
Sandstone (composed predominantly of Quartz, SiO2, with Feldspar and Clay minerals)
Tumbled quartz-rich stone, likely milky quartz
Quartz (SiO₂), possibly iron-stained milky quartz or quartzite
Milky Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Garnet (Almandine variety)
Almandine Garnet (Fe3Al2(SiO4)3)
Glauconitic Sandstone (Greenstone)
Glauconitic Siliciclastic Sandstone (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2
Quartz Pebble
Silicon dioxide (SiO2)
Black Slate
Slate (Metamorphic Rock)
Amphibolite
Amphibolite (rich in amphibole and plagioclase feldspar)
Quartz-rich metamorphic rock, likely quartzite
Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with feldspar, mica, and iron-oxide impurities
Quartzite Chert Pebble
Sedimentary Chert / Metamorphic Quartzite (SiO2)
Metallic sulfide ore, likely pyrite-bearing rock
Pyrite (FeS₂), possibly with chalcopyrite and quartz/host rock
Weathered banded metamorphic rock, likely gneiss
Banded gneiss; commonly quartz–feldspar–mica assemblage
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
Coquina / Fossiliferous Limestone
Calcite-rich Bioclastic Sedimentary Rock (CaCO3)
Chert (specifically Yellow/Common Opal or Jasper mixture)
Silicon Dioxide (SiO2)
Precious Opal
SiO2·nH2O (Hydrated Silicon Dioxide)
Sandstone
Arenite (SiO2 principal)
Shale
Shale (clay-rich mudstone)
Aquamarine
Beryl (Be3Al2Si6O18), specifically the blue-green variety
Banded Gneiss
Gneiss (Metamorphic Rock)
Slate
Foliated Metamorphic Slate
Gneiss (with Quartzite layers)
Gneissic Metamorphic Rock
Quartz
Silicon Dioxide (SiO2)