Flint / Chert (or fossiliferous nodule)
Microcrystalline quartz (SiO2)
sedimentary
Category
Synthetic Material (Not A Rock Or Mineral)
Browse synthetic material (not a rock or mineral) specimens identified by the Rock Identifier community.
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Sandstone
Arenite (SiO2 based with various cements)
sedimentary
Chert (with Quartz Vein)
Chert (Siliceous sedimentary rock, predominantly Microcrystalline Quartz SiO2)
sedimentary
White Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, formula: SiO2)
sedimentary
Granite
Phaneritic Felsic Igneous Rock
igneous
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Iron Oxide cement)
sedimentary
Olivine in Basalt matrix
Peridotite (Mg, Fe)2SiO4
igneous
Ocellar Rhyolite
Rhyolite (featuring orbicular/ocellar quartz and feldspar textures)
igneous
Blue sodalite-bearing rock, likely sodalite in nepheline syenite
Sodalite (Na₈Al₆Si₆O₂₄Cl₂), possibly in nepheline syenite
mineral
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
mineral
Rounded quartz-rich cobble, likely granite-derived stone
Granite or granitic gneiss, composed mainly of quartz, feldspar, and minor mica
igneous
Sandstone
Arenite (primarily SiO2)
sedimentary
Muscovite Mica
Muscovite KAl2(AlSi3O10)(OH)2
mineral
Dark basalt or basaltic volcanic rock
Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase feldspar, pyroxene, and often olivine
igneous
Fossilized Brachiopod
Phylum Brachiopoda (likely Order Spiriferida or Orthida)
fossil
Red Sandstone
Arenite (Ferruginous Sandstone)
sedimentary
Quartz Breccia with Iron Staining
Tectonic or Sedimentary Breccia (SiO2 with Fe2O3)
sedimentary
Tumbled blue-green stone, likely aquamarine-bearing pegmatite or blue apatite
Probable fluorapatite, Ca5(PO4)3(F,Cl,OH), though visual identification is uncertain
mineral
Quartz-rich rock, possibly milky quartz or quartzite
Quartz (SiO₂), potentially quartzite if the grains are fused
mineral
Banded Gneiss
Gneiss (Metamorphic rock)
metamorphic
Tumbled rose quartz
Rose quartz (pink quartz), silicon dioxide, SiO₂
mineral
Fossiliferous Limestone containing a Brachiopod or Mollusk Impression
Biogenic Sedimentary Rock / Fossiliferous Limestone
sedimentary
Red Sandstone
Arenite (primarily Quartz with Hematite cement)
sedimentary
Orbicular jasper / brecciated jasper
Silica-rich microcrystalline quartz (chalcedony), commonly with iron oxides and altered volcanic fragments
metamorphic
Sandstone (Quartzose)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Red Sandstone Pebble
Arenite with iron oxide (Hematite)
sedimentary
Sandstone (Ferruginous)
Arenite with Iron Oxide cement (SiO2 + Fe2O3)
sedimentary
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Serpentinite (likely)
Serpentinite, dominated by serpentine-group minerals (antigorite, lizardite, or chrysotile)
metamorphic
Chert with Quartz Veining
Silicon Dioxide (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO₂ / Silicon Dioxide)
mineral
Iron-stained garnet-bearing rock, possibly almandine garnet
Garnet-group silicate, likely almandine (Fe₃Al₂Si₃O₁₂), in a quartz–iron-oxide matrix
mineral
Mudstone
Lutylite (group of fine-grained sedimentary rocks)
sedimentary
Serpentine
Hydrous magnesium iron silicate, (Mg,Fe)3Si2O5(OH)4
metamorphic
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Limestone
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Mosasaur Tooth Fossil
Mosasaurus sp.
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
igneous
Sodalite
Sodalite - Na8(Al6Si6O24)Cl2
mineral
Quartzite Pebble
Quartzite (SiO2)
metamorphic