Mudstone
Lutylite (group of fine-grained sedimentary rocks)
sedimentary
Category
Sedimentary Rock (Altered)
Browse sedimentary rock (altered) specimens identified by the Rock Identifier community.
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Quartz-rich hydrothermal ore rock, likely gold-bearing quartz vein
Milky quartz (SiO₂) with iron-oxide staining and probable sulfide minerals; host rock may be schist or altered granite
metamorphic
Geode
Quartz / Chalcedony nodule
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Starfish Fossil
Asteroidea fossil
fossil
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Slate
Foliated Metamorphic Rock (Mainly composed of Quartz, Illite, Chlorite)
metamorphic
Dalmatian Stone
Aplite (often incorrectly called Dalmatian Jasper)
igneous
Coal (Bituminous / Anthracite)
Organic Sedimentary Rock (Carbonaceous Rock)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) within a geode
mineral
Sandstone
Sandstone (clastic sedimentary rock)
Rock
Sandstone
Arenite
sedimentary
Gravel / Crushed Stone
Aggregate (mixed mineral rock fragments)
sedimentary
Seashell (Calcium Carbonate)
Calcium Carbonate (CaCO3)
mineral
Rounded pale-green pebble, likely serpentinite or altered basalt
Probable serpentinite (serpentine-group minerals) or weathered mafic rock; exact identification requires testing
igneous
Sandstone (Weathered Cobble)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Quartz Geode in Sedimentary Host Rock
Silicon Dioxide (SiO2) in Carbonate Matrix
sedimentary
Conglomerate
Conglomerate (Sedimentary Rock)
sedimentary
Conglomerate
Conglomerate (Detrital Sedimentary Rock)
sedimentary
Sandstone
Arenite (SiO2 principal)
sedimentary
Fancy Jasper
Chalcedony (cryptocrystalline quartz) with inclusions
Mineral
Sandstone (Ferruginous)
Arenite (Siliclastic Sedimentary Rock)
sedimentary
Banded Sedimentary Rock
Sedimentary rock with Liesegang banding
sedimentary
Granite Pebble
Intrusive Igneous Rock
igneous
Quartz Geode with Calcite
Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3)
mineral
Limestone
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Sandstone (Pebble)
Arenite
sedimentary
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone
Arenite
sedimentary
Siltstone / Slate
Siltstone / Low-grade Slate
sedimentary
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
Painted Sandstone
Sandstone (clastic sedimentary rock) with acrylic/artistic coating
sedimentary
Fossil bivalve or brachiopod in sedimentary rock
Unidentified fossil shell impression; likely a ribbed bivalve or brachiopod preserved in shale/siltstone
fossil
Clear Quartz (Cut/Faceted Gemstone)
Silicon Dioxide (SiO2)
gemstone
Quartz Geode
Silicon Dioxide (SiO2) within a sedimentary or igneous host
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Shale
Shale (Consolidated fine-grained clay/silt)
sedimentary
Sandstone (with potentially high Feldspar/Arkose content)
Clastic sedimentary rock (SiO2 dominated)
sedimentary