River Cobble (Gneiss/Migmatite)
Gneissic Metamorphic Rock (composed mainly of Quartz, Feldspar, and Biotite)
metamorphic
Category
Rock (Likely Sedimentary)
Browse rock (likely sedimentary) specimens identified by the Rock Identifier community.
Calcite
Calcite (CaCO₃, Calcium Carbonate)
Mineral
Schist
Schist (various mineralogical compositions including mica, chlorite, talc, etc.)
Metamorphic
Gneiss (specifically a Granitic Gneiss specimen)
Gneiss (high-grade metamorphic rock primarily composed of Quartz, Feldspar, and Biotite/Amphibole)
metamorphic
Quartz
Silicon Dioxide (SiO2)
Mineral
Quartz
Quartz (SiO2, Silicon Dioxide)
Mineral
Zebra Rock (Zebra Stone / Ribbon Stone)
Siltstone with Ferruginous Banding (Primarily Quartz, Kaolinite, and Hematite)
sedimentary
Marble
Marbles are primarily composed of calcite (calcium carbonate, CaCO3) or dolomite (calcium magnesium carbonate, CaMg(CO3)2).
Metamorphic Rock
Diorite (possibly fine-grained variety or a related intermediate intrusive rock like a felsic gabbro or a dark granodiorite)
Diorite (Igneous rock, intrusive, intermediate composition)
Igneous Rock
Orthoclase Feldspar (or K-Feldspar)
Orthoclase (KAlSi3O8)
Mineral
Quartz with Iron Stains
Quartz (SiO2) with iron oxide/hydroxide staining
Mineral
Gneiss
Gneiss (pronounced 'nice')
Metamorphic Rock
Smoky Quartz
SiO2 (Silicon Dioxide)
Mineral
Quartz
Silicon Dioxide (SiO2)
Mineral
Quartz
Quartz (SiO₂)
Mineral
Agate
Agate (a variety of Chalcedony, SiO2)
Mineral
Ocean Jasper
Silicon Dioxide (SiO2) with various inclusions
igneous/sedimentary mixed (Orbicular Jasper)
Jasper
Silicon Dioxide (SiO2)
Mineral
Limonite (Iron Ore)
Hydrous Iron Oxide (goethite, lepidocrocite)
Mineral
Note: Image shows a biological specimen (Rat), not a rock. Representative geological equivalent: Galena (due to lead-grey colors in fur).
Galena (PbS)
mineral
Quartz
Quartz (Silicon Dioxide, SiO2)
Mineral
Banded Gneiss
Gneiss (variable mineral composition)
metamorphic
Blue Quartz
Quartz (SiO2) with inclusions
Mineral
Lapis Lazuli (blue bead) and Moss Agate (green heart)
Lapis Lazuli (lazurite-based rock) and Moss Agate (SiO2 with manganese/iron inclusions)
metamorphic (Lapis) and sedimentary/igneous assoc. (Moss Agate)
Quartz
Quartz (SiO2)
Mineral
Quartz
Silicon Dioxide (SiO2)
Mineral
Banded Gneiss
Gneiss (pronounced "nice")
Metamorphic Rock
Quartz (Milky Quartz)
Quartz (SiO2 - Silicon Dioxide)
Mineral
Turritella Agate (Elimia Agate)
Silicified Elimia tenera (formerly misidentified as Turritella)
sedimentary (silicified fossiliferous chalcedony)
Veined Quartz
SiO2 (Silicon Dioxide)
Mineral
Quartz Geode/Druzy Quartz
Quartz (SiO₂)
Mineral
Glauconitic Sandstone (or Greensand)
Glauconitic Siliciclastic Rock (Containing (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)
sedimentary
Granite (phaneritic background) with Limestone/Calcite carving
Felsic Igneous Plutonic Rock (background) / Calcium Carbonate (CaCO3) (carving)
igneous and sedimentary
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
Mineral
Sulfur on Aragonite
Sulfur (S) and Aragonite (CaCO3)
Mineral
Fuchsite Quartzite
Fuchsite-bearing Quartzite
Metamorphic
Quartz
Quartz (SiO₂ - Silicon Dioxide)
mineral
Amber (Cherry or Red variety)
Succinite (with various trace amounts of organic compounds)
Organic Gemstone (not a rock)
Quartz Druzy on Agate (River Cobble)
Silicon Dioxide (SiO2)
Mineral / Sedimentary (often associated with volcanic hosts)
Banded Gneiss
Gneiss
Metamorphic
Quartz
Silicon Dioxide (SiO₂)
Mineral
Quartz (Tumbled)
Silicon Dioxide (SiO2)
mineral