Chert (specifically Flint)
Silicon Dioxide (SiO2)
sedimentary
Category
Sedimentary Rock (Specifically A Concretion Or Possibly A Geode)
Browse sedimentary rock (specifically a concretion or possibly a geode) specimens identified by the Rock Identifier community.
Green Chert (Jasper)
Silicon Dioxide (SiO2)
sedimentary
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
sedimentary
Pyrite Geode
Iron Disulfide (FeS2)
mineral
Blue Chalcedony
Chalcedony (Silicon Dioxide, SiO2)
mineral
African Turquoise
Teal Jasper (Macro-crystalline Quartz/Sio2 + Inclusions of Copper, Iron, and Manganese)
sedimentary
Yellow Jasper
Cryptocrystalline quartz (SiO2) with iron inclusions
sedimentary
Blue Celestite (Celestine) Cluster
Strontium sulfate (SrSO4)
mineral
Yellow Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) within a secondary sedimentary structure
sedimentary
Sandstone Pebble with Iron Staining
Clastic Sedimentary Rock (primarily Quartz with Fe2O3 oxides)
sedimentary
Not a geological specimen
N/A (man-made object)
N/A
Quartz (likely Yellow/Orange variety, possibly Citrine or Chalcedony with iron staining)
Quartz (SiO₂)
Mineral
Siderite Concretion (Nodule)
Iron Carbonate (FeCO3) Concretion
sedimentary
Clear Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Quartz Geode (with Agate banding)
Silicon Dioxide (SiO2)
Sedimentary or Igneous (secondary formation)
Quartz
Quartz (SiO₂)
Mineral
Septarian Nodule (Dragon Stone)
Septarian concretion (composition: Calcium Carbonate / Calcite, Aragonite, and Limestone/Clay)
sedimentary
Chert (White-Tan variety)
Silicon dioxide (SiO2) / Microcrystalline Quartz
sedimentary
Chert (or possibly Flint)
Chert (variant: Flint)
Sedimentary
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Laterite (iron-rich nodule, possibly Bauxite as a subtype)
Laterite (composed of various minerals including goethite, hematite, gibbsite, etc.)
Sedimentary
Agate (specifically, multi-colored or pastel-dyed agate)
Silicon dioxide (SiO2) - specifically, a cryptocrystalline variety of quartz known as Chalcedony, with banding classified as Agate. (If it were Fluorite, the chemical formula would be Calcium Fluoride - CaF2).
Mineral
Quartz (Druzy)
Silicon Dioxide (SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Septarian Nodule (Thunder Egg)
Septarian Concretion (CaCO3 + CaMg(CO3)2 + SiO2)
sedimentary
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Quartz Pebble (Geode-like)
Silicon Dioxide (SiO2)
Mineral
Polygenetic Conglomerate (Puddingstone)
Conglomerate (SiO2 matrix with mixed clasts)
sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) - Impure Cryptocrystalline Quartz
sedimentary
Conglomerate (or Breccia)
Clastic Sedimentary Rock (Conglomeratic)
sedimentary
Moqui Marble (Shaman Stone)
Ironstone Concretion (Fe2O3) - primarily Hematite or Goethite shell with Sandstone core
sedimentary
Jasper (specifically Polychrome or Desert Jasper)
Silicon Dioxide (SiO2) with iron oxide and other mineral impurities
sedimentary (chemical/biological origin)
Red Chert (Jasper)
Chert / Microcrystalline Quartz (SiO2)
sedimentary
Limestone (specifically Iron-stained or Argillaceous Limestone)
Calcium Carbonate (CaCO3) with Iron Oxide (Fe2O3) impurities
sedimentary
Agate (Grey Agate Slice)
Microcrystalline Quartz (SiO2)
mineral
Agate (specifically, likely a geode slice or nodule)
Agate (a variety of Chalcedony, with chemical formula SiO2)
Mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
Mineral
Quartz in Matrix (possibly Basalt or Siltstone host)
Silicon Dioxide (SiO2) in Host Rock
mineral
Amphibolite (specifically Hornblende Schist/Gneiss)
Amphibole-rich Metamorphic Rock
metamorphic
Chert (Flint Nodules)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary