River Rocks (Black)
Various lithologies (e.g., basalt, chert, obsidian for black varieties), mechanically rounded clasts
Sedimentary
Category
Man Made (Synthetic Rock)
Browse man made (synthetic rock) specimens identified by the Rock Identifier community.
Sandstone (with potentially high Feldspar/Arkose content)
Clastic sedimentary rock (SiO2 dominated)
sedimentary
Sandstone (likely Arkosic)
Clastic Sedimentary Rock
sedimentary
Druzy Quartz on Matrix (likely Limestone or Sandstone)
Silicon Dioxide (SiO2) with various trace impurities
Mineral on Sedimentary Rock
Breciated Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Shale
Lutaceous sedimentary rock
sedimentary
Shale
Fissile mudstone (Shale)
sedimentary
Ironstone Concretion (Ironstone Gourd)
Limonite/Goethite Concretion (FeOO(H))
sedimentary
Sandstone (Quartzose)
Arenite (primarily SiO2)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Dark-colored Igneous Rock (likely Basalt or Diabase)
Basalt (extrusive igneous) or Diabase (intrusive igneous)
Igneous Rock
Grey Limestone Pebble
Limestone (Calcium Carbonate - CaCO3)
sedimentary
Sandstone (likely Greywacke or Lithic Sandstone)
Arenite / Wacke
sedimentary
Shale or Slate with Quartz Veins
Shale (fine-grained clastic sedimentary rock) or Slate (low-grade metamorphic rock formed from shale) with Quartz (SiO2) veins
Metamorphic, likely Sedimentary with Quartz veins
Quartz Vein Rock
Quartz (Silicon Dioxide, SiO2)
igneous
Slickenside
Tectonic Fault Scarp Surface
metamorphic
Basalt with Calcite Veins
Basalt (Mafic Volcanic Rock)
igneous
Basalt
Basalt (Mafic volcanic rock)
igneous
Basalt
Basalt (Aphanitic Mafic Igneous Rock)
igneous
Serpentinite
Serpentinite (complex silicate minerals including lizardite, chrysotile, and antigorite: (Mg,Fe)3Si2O5(OH)4)
metamorphic
Pink Granite
Phaneritic Plutonic Igneous Rock (high K-feldspar)
igneous
Red Sandstone
Sandstone (principally Quartz with Iron Oxide coating)
sedimentary
Fish Fossil in Limestone
Lycoptera (likely) in Micritic Limestone
sedimentary
Quartz-veined Basalt
Amygdaloidal or Porphyritic Basalt with Silicon Dioxide (SiO2) vein
igneous
Yellow Chert or Jasper
Microcrystalline Quartz (SiO2)
sedimentary
River Pebble (Quartz/Jasper)
Silicon Dioxide (SiO2)
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Fossiliferous Chert with Brachiopod Impression
Chert (SiO2) containing Brachiopoda fossil remains
sedimentary
Gneiss (Pebble)
Gneiss
metamorphic
Brecciated Jasper
Silicon Dioxide (SiO2) with Hematite impurities
sedimentary
Chert (Yellow/Tan Variety)
Chert (SiO2)
sedimentary
Slate with Quartz Vein
Foliated Metamorphic Rock (Mainly Quartz, Muscovite, Chlorite)
metamorphic
Quartzite River Rock
Quartzite (primarily SiO2)
metamorphic
Unakite
Epidotized Granite
metamorphic
Shale
Fissile mudrock (composed of clay-sized particles and detrital grains)
sedimentary
Sandstone or Quartzite
Arenite (if sedimentary) / Quartzite (if metamorphic)
Sedimentary or Metamorphic
Sandstone (Glacial Cobble)
Arenite / Sedimentary Rock (primarily SiO2)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) in Geode form
sedimentary
Sandstone (with Iron Staining)
Clastic sedimentary rock (SiO2 with Fe2O3 oxides)
sedimentary
Vesicular Basalt with Epidote
Vesicular Basalt (Mg, Fe)2SiO4 with Epidote (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH))
igneous
Quartzite with Hematite staining
Quartzite (SiO2) with iron oxide inclusions
metamorphic
Quartzite (River Pebble)
Meta-quartzite (composed primarily of SiO2)
metamorphic