River Quartzite Siltstone
Quartz-rich Meta-siltstone (SiO2 dominated)
metamorphic
Category
Organic Structure (Not A Rock)
Browse organic structure (not a rock) specimens identified by the Rock Identifier community.
Chert (River Pebble)
Microcrystalline silicon dioxide (SiO2)
sedimentary
Chert (Jasper)
Silicon Dioxide (SiO2)
sedimentary
Serpentine
Antigorite, Lizardite, or Chrysotile (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4
metamorphic
Granite
Granite (Felsic Plutonic Rock)
igneous
Basalt with Calcite Veins
Basalt (Mafic Volcanic Rock)
igneous
White Topaz
Aluminum Silicate Fluoride Hydroxide; Al2SiO4(F,OH)2
mineral
Basalt
Basalt (Mafic volcanic rock)
igneous
Metaconglomerate
Protolith: Conglomerate (comprising SiO2, Al2O3, etc.)
metamorphic
Amber
Resinite (Succinite if from the Baltic); Chemical Formula: C10H16O (approximate)
Organic Diamond/Gemstone (often associated with Sedimentary sequences)
Concrete / Anthropogenic Conglomerate
Man-made composite material (Portland cement, aggregate, and water)
not a natural rock
Asphalt (Bituminous Slate/Sandstone)
Asphaltum / Bituminous Rock
sedimentary
Milky Quartz with Country Rock contact
Silicon Dioxide (SiO2) in contact with Metamorphic/Igneous rock
mineral
Travertine (Tufa)
Chemical Sedimentary Limestone (CaCO3)
sedimentary
Amber
Succinite (specific to Baltic amber), fossilized tree resin
mineraloid
Garnet Schist
Almandine-Muscovite Schist
metamorphic
Ironstone Concretion
Siderite or Hematite Concretion
sedimentary
Fossil Coral (Favosites)
Favosites (Order: Tabulata, Phylum: Cnidaria)
sedimentary
Chert (Black Chert/Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Sandstone with Quartz Vein
Arenite with SiO2 intrusion
sedimentary
Tiger's Eye (likely Hawk's Eye variant)
Pseudomorph of Quartz after Crocidolite (SiO2)
metamorphic
Sandstone (with Lichen)
Arenite (primarily SiO2)
sedimentary
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
River Pebble (Likely Chert or Fine-Grained Sandstone/Quartzite)
Siliciclastic clast (likely Chert or Quartzarenite/Quartzite pebble)
Sedimentary
Chalcedony (Agate)
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone (with Iron Staining)
Clastic Sedimentary Rock (primarily Quartz, SiO2)
sedimentary
Chert (varieties include Flint and Jasper)
Silicon Dioxide (SiO2)
sedimentary
Chert (specifically Red Chert or Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (specifically Gray/Blue Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Tiger's Iron
Pseudomorphic Quartz Aggregate (contains SiO2 with Fe2O3 and FeOOH)
metamorphic
Granite
Granite (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Schist
Mica Schist (Medium-grade Metamorphic Rock)
Metamorphic
Pearl (with Peridot)
Calcium carbonate (CaCO3) + Conchiolin; Peridot: Magnesium iron silicate (Mg, Fe)2SiO4
mineral
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
sedimentary
Granodiorite
Granodiorite (containing Quartz, Plagioclase Feldspar, Biotite, and Hornblende)
igneous
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Fossiliferous Limestone (containing Brachiopods)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Boxwork Quartz / Septarian Jasper
Boxwork (SiO2 with iron oxide inclusions)
metamorphic
Botryoidal Chalcedony (Desert Rose / Agate)
Silicon Dioxide (SiO₂)
Mineral variant
Petrified Wood
Silicified Wood (SiO2 - Silicon Dioxide)
metamorphic