Mixed pebble collection, including likely flint, quartzite, and fossil material
Varied silicate rocks; visible specimen may include chert (microcrystalline SiO₂), quartzite, and a possible fossil
sedimentary
Category
Rock (Likely Sedimentary)
Browse rock (likely sedimentary) specimens identified by the Rock Identifier community.
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Likely serpentine pebble
Serpentinite; predominantly serpentine-group minerals, Mg₃Si₂O₅(OH)₄
metamorphic
Ferruginous Sandstone (with Pyrite/Gold associations)
Ferruginous Arenite (SiO2 + Fe2O3)
sedimentary
Milky quartz-bearing rock, possibly quartzite
Quartz (SiO₂), likely in a quartzite or quartz-rich metamorphic matrix
metamorphic
Sandstone
Arenite (SiO2 principal)
sedimentary
Weathered granite or granitic gneiss
Granite; primarily quartz, feldspar, and mica (possibly metamorphosed to gneiss)
igneous
Quartz (Milky/Chalcedony variety)
Silicon Dioxide (SiO2)
mineral
Coal
Coal (Sedimentary Rock / Organic Rock)
sedimentary
Basalt River Cobble
Basalt (Aphanitic Mafic Volcanic Rock)
igneous
Petrified Wood
Silicified Wood (primarily SiO2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Chalcedony (Carnelian/Agate variety)
Silicon Dioxide (SiO2) with trace hematite/iron impurities
mineral
Vesicular Basalt
Basalt (Mafic Extrusive Volcanic Rock)
igneous
Chert / Flint
Silicon dioxide (SiO2)
sedimentary
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Flint (chert), likely brown flint
Microcrystalline quartz/chalcedony (SiO₂)
sedimentary
Gneiss (specifically Granitic Gneiss)
Gneiss
metamorphic
Pink Granite
Felsic Plutonic Rock (primarily Quartz, Potassium Feldspar, and Plagioclase)
igneous
Bornite (“peacock ore”), likely weathered copper sulfide
Bornite, Cu₅FeS₄; possibly chalcopyrite, CuFeS₂, with iridescent tarnish
mineral
Banded Sedimentary Rock
Sedimentary rock with mineral veins/banding
sedimentary
Chert (Jasper variety)
Silicon dioxide (SiO2)
sedimentary
Specular Hematite with Quartz and Limonite
Hematite (Fe2O3) with Quartz (SiO2) and Limonite (FeO(OH)·nH2O)
Mineral
Quartzite
Quartzite (SiO2)
metamorphic
Likely weathered metallic mineral or slag fragment
Indeterminate; possibly iron-rich sulfide/oxide material or industrial slag
mineral
Weathered basalt (likely vesicular basalt)
Basalt; primarily plagioclase feldspar, pyroxene, and commonly olivine
igneous
Painted Sandstone
Sandstone (clastic sedimentary rock) with acrylic/artistic coating
sedimentary
Polished turquoise
Turquoise — hydrated copper–aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O
gemstone
Granite
Coarse-grained granitic rock, chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende
igneous
Chert (Jasper)
Cryptocrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified wood (primarily SiO2)
sedimentary
Yellow Chert (Microcrystalline Quartz)
Chert / SiO2 (Silicon Dioxide)
sedimentary
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) in matrix
Mineral in Metamorphic/Igneous Host
Cockle Shell Fossil
Cardiidae family (Bivalvia)
fossil
Cannonball Concretion
Calcite-cemented Sandstone Concretion
sedimentary
Fossil Brachiopod or Mollusk Cast
Phylum Brachiopoda / Mollusca internal mold
fossil
Sandstone Pebble
Sedimentary Rock (Quartzose Sandstone)
sedimentary
Seashell Fossil
Gastropoda fossil
fossil
Rhyolite or jasper-bearing volcanic rock
Rhyolite, likely altered and silicified; red coloration may come from hematite
igneous
Milky Quartz (with Iron Oxide staining)
Quartz (Silicon Dioxide - SiO2)
mineral
Coal (Bituminous / Anthracite)
Organic Sedimentary Rock (Carbonaceous Rock)
sedimentary
Weathered granite (likely pegmatitic granite)
Granite; predominantly quartz (SiO₂), feldspar, and mica, with possible iron-oxide alteration
igneous
Petrified Wood
Silicified wood (primarily quartz, SiO2)
fossil