Chert (Flint)
Microcrystalline Quartz (SiO2)
Category
Browse sedimentary (chemically precipitated) or metamorphic specimens identified by the Rock Identifier community.
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
Chert / Chalcedony
Microcrystalline Quartz (SiO2)
Green Calcite
Calcite (Calcium Carbonate, CaCO3)
Chert (Field Stone)
Chert (Silicon Dioxide, SiO2)
Orange Calcite
Calcium Carbonate (CaCO3)
Chert (Jasper)
Silicon Dioxide (SiO2)
Yellow Calcite
Calcium Carbonate (CaCO3)
Chert (Flint Nodules)
Microcrystalline quartz (SiO2)
Limonite (Iron Ore Congcretion)
Limonite (a mixture of hydrated iron(III) oxide-hydroxides, FeO(OH)·nH2O)
Zoisite with Rubellite (Ruby in Zoisite)
Zoisite with inclusions of Hornblende (Anyolite)
Zoisite with Ruby
Anyolite (Calcium aluminum hydroxy silicate with Corundum) Ca2Al3(SiO4)3(OH)
Tumbled yellow chalcedony (likely citrine or yellow quartz)
Quartz, SiO₂; potentially microcrystalline chalcedony
Geode (Unopened Keokuk Geode)
Silicon Dioxide (SiO2) - Chalcedony / Quartz exterior
Quartz Geode with Iron Staining
Silicon Dioxide (SiO2) with Limonite/Hematite inclusions
Red Jasper and Mookaite Jasper
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Quartz Geode
Crystalline Silicon Dioxide (SiO2) in a Geodic Concretion
Quartz Pebble (Geode-like)
Silicon Dioxide (SiO2)
Agate
Silicon Dioxide (SiO2)
Pink Opal (Common Opal)
Amorphous Hydrated Silica (SiO2·nH2O)
Amethyst Geode
Amethyst (Silicon Dioxide), Formula: SiO2
Quartz Pebble
Silicon dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Limestone
Calcium Carbonate (CaCO3)
Quartz / Common Gravel
Silicon Dioxide (SiO2)
Barite
Barium sulfate (BaSO4)
Pyrite
Iron Sulfide (FeS2)
Magnetite (Iron Ore)
Iron(II,III) oxide (Fe3O4)
Chert (Field Stone)
Microcrystalline Quartz (SiO2)
Chert / Jasper
Silicon Dioxide (SiO2)
Garnet-Mica Schist
Garnetiferous Porphyroblastic Schist
Quartz
Silicon Dioxide (SiO2)
Gneiss
Metamorphic Gneiss
Flint
Sedimentary cryptocrystalline quartz (SiO2)
Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock exposed to metamorphic heat/pressure; Chemical composition is approximately 86%–98% Carbon)
Chert (within Limestone)
Silicon Dioxide (SiO2) within Calcium Carbonate (CaCO3)
Banded Gneiss
Metamorphic Gneiss
Flint in Chalk
Sedimentary nodular chert within chalk (SiO2)
Honey calcite (orange calcite)
Calcite — calcium carbonate, CaCO₃
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Quartz Geode
Macrocrystalline Quartz (SiO2) within a geode structure
Agate Geode
Cryptocrystalline Quartz (SiO2)