Chert (or Flint)
Silicon dioxide (SiO2)
sedimentary
Category
Man Made Object (Coin)
Browse man made object (coin) specimens identified by the Rock Identifier community.
Stromatolite
Laminated biogenic sedimentary structure (formed by Cyanobacteria)
sedimentary
Schorl (Black Tourmaline) in Quartz or Feldspar Matrix
NaFe3Al6(BO3)3Si6O18(OH)4 (Schorl) in Granitic Pegmatite
igneous
Druzy Quartz on Matrix (likely Limestone or Sandstone)
Silicon Dioxide (SiO2) with various trace impurities
Mineral on Sedimentary Rock
Basalt
Mafic volcanic rock (Silicon dioxide 45-52%)
igneous
Mahogany Obsidian Arrowhead
Volcanic Glass with Hematite/Magnetite inclusions (Amorphous Silicon Dioxide)
igneous
Obsidian (Apache Tear)
Obsidian / Amorphous Volcanic Glass (main component: SiO2)
igneous
Quartz with Iron Stains
Quartz (SiO2) with iron oxide/hydroxide staining
Mineral
Quartz (likely Rose Quartz or Milky Quartz based on color)
Quartz (SiO2 - Silicon Dioxide)
Mineral
Granite (weathered)
Felsic Intrusive Igneous Rock (composed of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Limonitic Sandstone with Inclusion
Limonitic Quartz Sandstone (primarily SiO2 with FeO(OH)·nH2O)
sedimentary
Queen Conch Shell (Biogenic Calcium Carbonate)
Aliger gigas (synonym Strombus gigas); Composition: Aragonite (CaCO3)
mineral
Quartz (beads)
SiO2 (Silicon Dioxide)
Mineral
Smoky Quartz
SiO2 (Silicon Dioxide)
Mineral
Fuchsite
K(Al,Cr)2(AlSi3O10)(OH)2 (Chromium-rich Muscovite)
mineral
Marble
Marble (primarily Calcite, CaCO3 or Dolomite, CaMg(CO3)2)
Metamorphic Rock
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Epidote with Quartz and Feldspar
Ca2(Al2,Fe3+)(SiO4)3(OH) (Epidote complex)
metamorphic
Iridescent Ammonite Fossil
Ammonoidea (subclass); Composition: Aragonite (Calcium Carbonate, CaCO3) often replaced by Calcite or Pyrite
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Gneiss
Gneiss (High-grade regional metamorphic rock)
metamorphic
Red Garnet
Pyrope-Almandine series (Mg3Al2(SiO4)3 to Fe3Al2(SiO4)3)
mineral
Granite
Phaneritic Plutonic Felsic Rock (SiO2, KAlSi3O8, NaAlSi3O8, CaAl2Si2O8)
igneous
Ambergris
Ambrein (C30H52O Derivative)
Organic (Zoogenic)
Quartz
Silicon Dioxide (SiO2)
Mineral
Quartz
Quartz (Silicon Dioxide, SiO2)
Mineral
Diamond
Diamond (C)
Mineral
Granite
Granite (a common name for a felsic intrusive igneous rock)
Igneous Rock
Red Jasper (beads)
Silicon Dioxide (SiO2) with iron inclusions
Sedimentary Rock
Laterite
Laterite (primarily composed of hydrated oxides of iron and aluminum)
Sedimentary Rock (as a residual soil/rock, it's often considered a type of sedimentary rock due to its formation from weathering, though it can cross into soil science)
Granite
Granite (a plutonic igneous rock)
Igneous
Rose Quartz
SiO2 (Silicon Dioxide)
mineral
Sandstone (likely Quartzose Sandstone)
Arenite (composed primarily of SiO2)
sedimentary
Red Quartzite
Quartzite (SiO2 with iron oxide impurities)
metamorphic
Ruby in Zoisite
Ruby (Corundum, Al2O3) in Zoisite (Calcium aluminum silicate hydroxide, Ca2Al3(SiO4)3(OH)) with some Hornblende
Metamorphic Rock (specifically a rock composed of minerals)
Garnet Schist
Almandine Garnet-Mica Schist (X₃Y₂(SiO₄)₃)
metamorphic
Basalt
Basalt (Mafic Extrusive)
igneous
Quartz (Milky Quartz)
Quartz (SiO2 - Silicon Dioxide)
Mineral
Lapis Lazuli
Lazurite-rich metamorphic rock (complex silicate)
metamorphic
Quartzite
Quartzite (primarily SiO2)
metamorphic
Pyrite
Iron Pyrite (FeS₂)
Mineral
Greywacke (likely)
Greywacke (a type of sandstone)
Sedimentary