River Cobble (Quartzite / Granitic Gneiss)
Metamorphic Quartzite / Granitic Gneiss
metamorphic
Category
Organic (Non Geological)
Browse organic (non geological) specimens identified by the Rock Identifier community.
Black Obsidian
Volcanic Glass (Amorphous Silicon Dioxide SiO2)
Igneous
Black Obsidian
Volcanic Glass (SiO2 with impurities)
igneous
Obsidian
Obsidian (Volcanic glass), SiO2 (major component)
igneous
Obsidian with Mahogany Phasing
Volcanic Glass (SiO2 + Fe2O3)
igneous
Obsidian
Obsidian (Volcanic Glass)
igneous
Petrified Wood
Silicified Wood (SiO2)
mineral
Obsidian (Black Obsidian)
Amorphous volcanic glass (primarily SiO2)
igneous
Petrified Wood
Silicified Wood (SiO2)
mineral
Quartzite Pebble with Pyrite Coating
SiO2 (Quartz) with FeS2 (Pyrite) inclusions or surface coating
metamorphic
Probable amber fragment
Amber (fossilized plant resin; chiefly amorphous organic resin, commonly dominated by succinite)
gemstone
Ferrosilicon Slag (Industrial Vitrified Glass)
Vitreous Silicate Residue
Antropogenic (Man-made industrial byproduct)
Quartzite
Metamorphic rock predominantly composed of Quartz (SiO2)
metamorphic
Quartzite
Quartzite (primarily SiO2)
metamorphic
Obsidian
Obsidian (Volcanic Glass, SiO2)
igneous
Grey River Stone (Quartz-rich Quartzite/Siltstone)
Quartzite / Meta-siltstone (primarily SiO2)
Metamorphic (low-grade)
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Shale
Shale (clastic sedimentary rock composed of silt and clay-sized particles)
sedimentary
Conglomerate
Conglomerate (SiO2, Al2O3, Fe2O3, CaCo3)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Fossilized Coral
Scleractinia (fossil order), primarily Calcium Carbonate (CaCO3)
sedimentary
Obsidian
Volcanic Glass (SiO2)
igneous
Slag
Ferrous Slag (Amorphous calcium-magnesium-aluminum silicates)
igneous (artificial/anthropogenic)
Quartzite with Garnet
Garnetiferous Quartzite (SiO2 + X3Y2(SiO4)3)
metamorphic
Limestone
Calcareous sedimentary rock (CaCO3)
sedimentary
Chert (Jasper)
Silicon Dioxide (SiO2)
sedimentary
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (and Jasper blend)
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Flint)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Chert / Flint
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Glauconitic Sandstone (Greensand pebble)
Glauconitic Quartz Sandstone (K(Fe,Al)2(Si,Al)4O10(OH)2)
sedimentary
Chert (and Limestone) River Cobble
Microcrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)
sedimentary
Chert (Jasper variety)
Chert (SiO2)
sedimentary
Chert (Black Chert/Flint)
Silicon Dioxide (SiO2)
sedimentary
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
igneous
Amber (Green variation)
Succinite
fossil
Rounded quartzite pebble
Quartzite, predominantly crystalline SiO₂
metamorphic
Rounded gray river pebble, likely basalt or andesite
Fine-grained mafic to intermediate volcanic rock; commonly basalt (plagioclase + pyroxene, sometimes olivine)
igneous
Black Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
igneous
Quartzite
Quartzite (primarily SiO2)
metamorphic
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
igneous