Chalcedony (Agate Pebble)
Silicon Dioxide (SiO2)
mineral
Category
Mineral (Tectosilicate)
Browse mineral (tectosilicate) specimens identified by the Rock Identifier community.
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Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
metamorphic
Smoky Quartz with Feldspar
SiO2 (Quartz) with KAlSi3O8 (Potassium Feldspar)
mineral
Prehnite
Prehnite, Ca2Al2Si3O10(OH)2
mineral
Tiger's Eye
Fibrous Quartz (SiO2) with iron inclusions
mineral
Rough Quartz (Milky Quartz Pebbles)
Silicon Dioxide (SiO2)
mineral
Gossan (Iron Hat) with Quartz and Chlorite
Limonite/Goethite-rich Gossan (FeO(OH)·nH2O) with inclusions of Quartz and Chlorite
Mineral/Metamorphic Substrate
Lazulite
Lazulite (Mg,Fe2+)Al2(PO4)2(OH)2
mineral
Banded Calcite (often sold as 'Mexican Onyx' or 'Calcite Onyx')
Calcite (Calcium Carbonate, CaCO3)
sedimentary
Quartz with inclusions (likely Chlorite or Hornblende) and country rock
SiO2 (Quartz) with associated ferromagnesian minerals
Mineral/Igneous/Metamorphic association
Granite
Granite (composed mainly of Quartz, Feldspar, and Mica)
igneous
Granite fragment
Granite (Felsic Plutonic Rock)
igneous
Shale
Shale
sedimentary
Gneiss (likely)
Gneiss
Metamorphic
Fossilized Oyster Shell
Exogyra or Ostrea (Gryphaeidae/Ostreidae family)
fossil
Sandstone (Ferruginous)
Arenite (composed primarily of SiO2 with Fe2O3 cement)
sedimentary
Malachite
Copper carbonate hydroxide Cu2CO3(OH)2
mineral
Sandstone (Ferruginous)
Arenite (Fe-rich)
sedimentary
Red Sandstone
Clastic sedimentary rock (primarily SiO2 with Fe2O3)
sedimentary
Red Sandstone
Arenite (primarily Quartz with Hematite cement)
sedimentary
Black Marble
Recrystallized Calcite (CaCO3)
metamorphic
Sandstone with Iron Oxide Staining
Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)
sedimentary
Sandstone (Red Sandstone)
Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide)
sedimentary
Red Sandstone
Arenite (with Iron Oxide)
sedimentary
Sandstone (with Iron Staining)
Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 oxides)
sedimentary
Sandstone (Quartzose)
Arenite (primarily SiO2)
sedimentary
Red Sandstone
Arenite with iron oxide (Hematite) cement
sedimentary
Turquoise (Blue Howlite / Magnesite imitation)
CuAl6(PO4)4(OH)8·4H2O (for natural Turquoise); Ca2B5SiO9(OH)5 (for Howlite)
mineral
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic Extrusive)
igneous
Granite
Granite (felsic intrusive igneous rock)
igneous
Blue Apatite
Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)
mineral
Howlite
Howlite (Ca2B5SiO9(OH)5)
mineral
Serpentinite
Serpentinite (composed primarily of serpentine-group minerals like antigorite, chrysotile, and lizardite; chemical formula varies but generally Mg3Si2O5(OH)4)
Metamorphic Rock
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Quartz in Host Rock
Silicon Dioxide (SiO2) in Rhyolite or Granite matrix
igneous
Fossilized Shark Tooth
Carcharhinus sp. (likely Bull or Requiem shark family)
sedimentary
Mica Schist with Quartz
Crystalline Schist (SiO2 + KAl2(AlSi3O10)(OH)2)
metamorphic
Green Aventurine
Silicon Dioxide (SiO2) with inclusions of Fuchsite
metamorphic
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Quartz-veined Metamorphic Rock
Quartz Vein in Phyllite or Schist (SiO2 in Silicate Matrix)
metamorphic
Sandstone with Quartz Vein
Arenite with SiO2 intrusion
sedimentary
Green Aventurine
Silicon Dioxide (SiO2+KAl2(AlSi3O10)(OH)2)
metamorphic