Chalcedony (Agate/Chert)
Microcrystalline Quartz (SiO2)
sedimentary
Category
Sedimentary Rock (Specifically A Clastic Sedimentary Rock Formed Into A Cobble)
Browse sedimentary rock (specifically a clastic sedimentary rock formed into a cobble) specimens identified by the Rock Identifier community.
Ferruginous Quartz
Silicon Dioxide (SiO2) with Iron Oxide (Hematite/Limonite) inclusions
mineral
Turquoise
Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)
mineral
Sandstone with Algae Growth
Arenite with Chlorophyta/Lichen
sedimentary
Coquina
Bioclastic Limestone (composed primarily of CaCO3)
sedimentary
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
mineral
Schist
Mica Schist
metamorphic
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Dream Amethyst (Chevron Amethyst)
Silicon Dioxide (SiO2) with iron impurities and gamma radiation exposure
Mineral
Jasper (likely Lake Superior Jasper)
Jasper (Silicon Dioxide, SiO2)
sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with Goethite/Limonite inclusions
sedimentary
Limonite (Iron Ore/Sandstone mixture)
Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix
mineral
Gneiss
Gneiss
metamorphic
Basaltic Tuff / Volcanic Breccia
Pyroclastic Breccia / Lithic Tuff
igneous
Red Sandstone
Arenite (Ferruginous Sandstone)
sedimentary
Chert (variations include Flint/Jasper)
Cryptocrystalline Silicon Dioxide (SiO2)
sedimentary
Turquoise
Turquoise (Hydrated phosphate of copper and aluminium) CuAl6(PO4)4(OH)8·4H2O
mineral
Banded Flint (Polished Stripe Flint)
Silicon Dioxide (SiO2) - variety of Chert
sedimentary
Chert / River Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Fossiliferous Limestone
Limestone (CaCO3 - Calcium Carbonate)
sedimentary
Quartz (specifically Citrine or Yellow Quartzite pebble)
Silicon Dioxide (SiO2)
mineral
Chert Concretion (with typical hematite/limonite staining)
Sedimentary Concretion (SiO2 with FeO(OH)⋅nH2O)
sedimentary
Zebra Jasper
Silicon dioxide (SiO2) with various impurities
Sedimentary
Dendritic Agate (River Pebble)
Silicon Dioxide (SiO2) with Manganese or Iron oxide inclusions
mineral
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary
Gold
Native Gold (Au)
mineral
Quartz / Common Opal Transition
Silicon Dioxide (SiO2)
mineral
Jasper (Iron-stained Quartz)
Silicon dioxide (SiO2) with iron oxide inclusions
sedimentary
Bauxite
Bauxite (Al(OH)3, γ-AlO(OH), and α-AlO(OH))
sedimentary
Limonite after Pyrite (Prophecy Stone)
Limonite (FeO(OH)·nH2O) replacing Pyrite (FeS2)
Mineral pseudomorph
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Quartz (Milk Quartz / Massive Quartz)
Silicon Dioxide (SiO2)
mineral
Geode (Unopened)
Silica-rich Concretion (primarily SiO2)
sedimentary
Aragonite Star Cluster
Aragonite (Calcium Carbonate - CaCO3)
mineral
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, formula: SiO2)
sedimentary
Greenschist
Chlorite schist (Metamorphic rock dominated by chlorite, epidote, and actinolite)
metamorphic
Clear Quartz
Silicon Dioxide (SiO2) / Rock Crystal
mineral
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Chert (Jasper variation)
Microcrystalline Quartz (SiO2)
sedimentary
Green Calcite
Calcium Carbonate (CaCO3)
mineral
Chalcedony (specifically Agate or Moonstone-like Quartz)
Silicon Dioxide (SiO2)
mineral
Chert (Holey Stone)
Microcrystalline Quartz (SiO2)
sedimentary