Banded chert or siliceous mudstone
Microcrystalline quartz (chalcedony), SiO₂; possibly ferruginous shale
sedimentary
Category
Rock (Likely Sedimentary)
Browse rock (likely sedimentary) specimens identified by the Rock Identifier community.
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Amethyst with Marcasite accents
Amethyst (Silicon Dioxide SiO2) and Marcasite (Iron Sulfide FeS2)
mineral
Glauconitic Sandstone with possible Trace Fossil
Glauconitic Sandstone (K(Fe,Al)2(Si,Al)4O10(OH)2)
sedimentary
Pink Granite
Phaneritic plutonic igneous rock (Alkali feldspar granite)
igneous
Garnet (likely Almandine)
Almandine Garnet, Fe3Al2(SiO4)3
mineral
Red Sandstone
Clastic Sedimentary Rock
sedimentary
Sandstone
Clastic Sedimentary Rock
sedimentary
Sandstone
Clastic Sedimentary Rock
sedimentary
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Chert (Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone (Common Quartz Pebble/Rock)
Sedimentary rock / Quartz arenite
sedimentary
Weathered serpentinite (likely serpentine-rich rock)
Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite and accessory minerals
metamorphic
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Quartz geode
Quartz (SiO₂), likely drusy/microcrystalline quartz lining a geode cavity
mineral
Quartz-veined Sandstone
Sedimentary rock with quartz vein (SiO2)
sedimentary
Amethyst (Agate/Chalcedony variety)
Silicon Dioxide (SiO2) with iron impurities
mineral
Obsidian (likely snowflake-free black volcanic glass)
Volcanic glass; predominantly rhyolitic silica melt (SiO₂-rich, noncrystalline)
igneous
Red Sandstone Pebble
Sedimentary quartz sandstone
sedimentary
Rounded gray river pebble, likely basalt or andesite
Fine-grained mafic volcanic rock; commonly basalt (plagioclase, pyroxene, ± olivine)
igneous
Quartz pebble (Quartztite fragment)
Silicon Dioxide (SiO2)
mineral
Ironstone Concretion / Chert Nodules
Iron-rich Sedimentary Concretion (Fe2O3 / SiO2 mix)
sedimentary
Iron-rich meteorite candidate
Unclassified iron meteorite or stony-iron meteorite; confirmation requires chemical and nickel testing
meteorite
Sandstone (Iron-stained)
Arenite with Limonite/Hematite staining
sedimentary
Garnet Schist
Garnetiferous Micaceous Schist
metamorphic
Red Granite
Phaneritic Felsic Igneous Rock (Quartz, Alkali Feldspar, Plagioclase)
igneous
Milky quartz (quartz-rich rock)
Quartz, silicon dioxide (SiO₂); likely massive quartz with minor iron-stained impurities
mineral
Amethyst-rich vesicular volcanic rock (probable amethyst basalt/scoria)
Quartz (SiO₂) in vesicular basaltic volcanic rock; precise identification requires testing
igneous
Jasper with Epidote
Silicon Dioxide (SiO2) with Calcium Aluminum Iron Silicate Hydrate
sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Sandstone Pebble
Sedimentary quartz arenite
sedimentary
Sandstone Concretion
Sedimentary Concretion (Quartz sand bound by mineral cement)
sedimentary
Sandstone Pebble
Sedimentary Rock (Quartzose Sandstone)
sedimentary
Weathered sandstone
Quartz-rich clastic sandstone, commonly arkosic or feldspathic
sedimentary
Chert (Chalcedony)
Cryptocrystalline Quartz (SiO2)
sedimentary
Banded Chert (Jasper/Agate)
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Jasper (Silica/Silicon Dioxide, SiO2)
sedimentary
Banded Chert (River Jasper)
Silicon Dioxide (SiO2) with impurities
sedimentary
Satin Spar (Selenite)
Gypsum (Calcium Sulfate Dihydrate, CaSO4·2H2O)
mineral
Iron-stained quartz-rich rock, possibly jasper/quartzite
Quartz (SiO₂) with iron-oxide staining; likely ferruginous quartzite or jasper
metamorphic
Fossilized Bone
Permineralized Vertebrate Bone
fossil
Chert (Chert / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary