Rock Identifier

Category

Organic Structure (Not A Rock)

Browse organic structure (not a rock) specimens identified by the Rock Identifier community.

Massive Quartz (Milky or Gray) (Silicon Dioxide (SiO2)) — mineral

Massive Quartz (Milky or Gray)

Silicon Dioxide (SiO2)

Granite (Granite (Phaneritic Quartz-Feldspar Plutonic Rock)) — igneous

Granite

Granite (Phaneritic Quartz-Feldspar Plutonic Rock)

Mahogany Obsidian (Volcanic Glass (predominantly SiO2 with inclusions of Hematite or Magnetite)) — igneous

Mahogany Obsidian

Volcanic Glass (predominantly SiO2 with inclusions of Hematite or Magnetite)

Fossiliferous Sandstone (with Brachiopod or Bivalve mold) (Clastic Sedimentary Rock with Macrofossil Mold) — sedimentary

Fossiliferous Sandstone (with Brachiopod or Bivalve mold)

Clastic Sedimentary Rock with Macrofossil Mold

Red Siltstone (or Red Shale) (Clastic Sedimentary Rock (Composition: primarily Quartz, Clay minerals, and Hematite Fe2O3)) — sedimentary

Red Siltstone (or Red Shale)

Clastic Sedimentary Rock (Composition: primarily Quartz, Clay minerals, and Hematite Fe2O3)

Green Calcite (Calcium Carbonate (CaCO3)) — mineral

Green Calcite

Calcium Carbonate (CaCO3)

Tiger's Eye (Pseudomorph of Crocidolite (SiO2 with iron oxides)) — mineral

Tiger's Eye

Pseudomorph of Crocidolite (SiO2 with iron oxides)

Banded Sandstone (Arenite with Liesegang banding) — sedimentary

Banded Sandstone

Arenite with Liesegang banding

Granite (Plutonic Igneous Rock (composed typically of SiO2, Al2O3, K2O, Na2O, CaO)) — igneous

Granite

Plutonic Igneous Rock (composed typically of SiO2, Al2O3, K2O, Na2O, CaO)

Quartz (on matrix) (Quartz (Silicon Dioxide, SiO₂)) — Mineral

Quartz (on matrix)

Quartz (Silicon Dioxide, SiO₂)

Lapis Lazuli (Lapis Lazuli (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2) — metamorphic

Lapis Lazuli

Lapis Lazuli (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2

Sandstone (Iron-stained) (Arenite (composed primarily of SiO2 with Fe2O3 staining)) — sedimentary

Sandstone (Iron-stained)

Arenite (composed primarily of SiO2 with Fe2O3 staining)

Orange Calcite (Calcium Carbonate (CaCO3)) — mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Gneiss (Gneissic Metamorphic Rock (Mineral composition: Quartz, Feldspar, Amphibole/Biotite)) — metamorphic

Gneiss

Gneissic Metamorphic Rock (Mineral composition: Quartz, Feldspar, Amphibole/Biotite)

Ferruginous Sandstone (Ironstone Nodules) (Ferruginous Quartz-Arenite (with Goethite/Hematite cement)) — sedimentary

Ferruginous Sandstone (Ironstone Nodules)

Ferruginous Quartz-Arenite (with Goethite/Hematite cement)

Gneiss (Foliated Metamorphic Rock (Gneiss)) — metamorphic

Gneiss

Foliated Metamorphic Rock (Gneiss)

Sandstone (Greywacke/Lithic Sandstone) (Arenite / Lithic Sandstone) — sedimentary

Sandstone (Greywacke/Lithic Sandstone)

Arenite / Lithic Sandstone

Gneiss (Metamorphic Rock) (Gneiss (variable mineral formula primarily containing Quartz, Feldspar, and Mica)) — metamorphic

Gneiss (Metamorphic Rock)

Gneiss (variable mineral formula primarily containing Quartz, Feldspar, and Mica)

Agate Geode Slice (with Druzy Quartz) (Silicon Dioxide (SiO2)) — mineral

Agate Geode Slice (with Druzy Quartz)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous) (Arenite with Iron oxide staining (SiO2 with Fe2O3)) — sedimentary

Sandstone (Ferruginous)

Arenite with Iron oxide staining (SiO2 with Fe2O3)

Fossilized Wood (with Coal and Limonite) (Petrified Wood (Silicified or Carbonized Flora)) — sedimentary

Fossilized Wood (with Coal and Limonite)

Petrified Wood (Silicified or Carbonized Flora)

Granite (Felsic Plutonic Rock (primarily SiO2)) — igneous

Granite

Felsic Plutonic Rock (primarily SiO2)

Amethyst (Silicon dioxide with iron impurities (SiO2)) — mineral

Amethyst

Silicon dioxide with iron impurities (SiO2)

Lepidolite (Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)) — mineral

Lepidolite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)

Sandstone (Banded) (Clastic Sedimentary Rock (primarily SiO2)) — sedimentary

Sandstone (Banded)

Clastic Sedimentary Rock (primarily SiO2)

Petrified Wood (Silicified wood (SiO2 - Silicon Dioxide)) — sedimentary

Petrified Wood

Silicified wood (SiO2 - Silicon Dioxide)

Granite Cobble (Granite (Phaneritic Igneous Rock)) — igneous

Granite Cobble

Granite (Phaneritic Igneous Rock)

Granite (Phaneritic Igneous Rock (Granitic)) — igneous

Granite

Phaneritic Igneous Rock (Granitic)

Sandstone (likely Graywacke or Arkose variant) (Clastic Sedimentary Rock (Lithic Sandstone)) — sedimentary

Sandstone (likely Graywacke or Arkose variant)

Clastic Sedimentary Rock (Lithic Sandstone)

Greenstone (Epidote/Chlorite-rich Metabasalt) (Greenschist / Epidosite (Ca2(Al,Fe)3(SiO4)3(OH))) — metamorphic

Greenstone (Epidote/Chlorite-rich Metabasalt)

Greenschist / Epidosite (Ca2(Al,Fe)3(SiO4)3(OH))

Chert (Flint) (Chert (Cryptocrystalline variety of Quartz, SiO2)) — sedimentary

Chert (Flint)

Chert (Cryptocrystalline variety of Quartz, SiO2)

Wishing Stone with Quartz Veins (Quartzite or Quartz-veined Metamorphic Rock (composed mainly of SiO2)) — metamorphic

Wishing Stone with Quartz Veins

Quartzite or Quartz-veined Metamorphic Rock (composed mainly of SiO2)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Sandstone (Arenite (composed primarily of SiO2)) — sedimentary

Sandstone

Arenite (composed primarily of SiO2)

Clear Quartz Crystal (Herkimer Diamond style) (Silicon Dioxide (SiO2)) — mineral

Clear Quartz Crystal (Herkimer Diamond style)

Silicon Dioxide (SiO2)

Chert (Iron-stained) (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Iron-stained)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (variant Flint/Jasper) (Microcrystalline Opaline Silica (SiO2)) — sedimentary

Chert (variant Flint/Jasper)

Microcrystalline Opaline Silica (SiO2)

Sedimentary Breccia (Breccia (Clastic Sedimentary Rock)) — sedimentary

Sedimentary Breccia

Breccia (Clastic Sedimentary Rock)

Chert (often called Flint when dark) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (specifically Tan/Gray Chert) (Microcrystalline quartz (SiO2)) — sedimentary

Chert (specifically Tan/Gray Chert)

Microcrystalline quartz (SiO2)

Black Pearl (Tahitian or Irradiated Type) (Organic gemstone (Calcium Carbonate with Conchiolin Binding)) — mineraloid

Black Pearl (Tahitian or Irradiated Type)

Organic gemstone (Calcium Carbonate with Conchiolin Binding)

White Marble (Recrystallized Calcite (CaCO3)) — metamorphic

White Marble

Recrystallized Calcite (CaCO3)