Chert (Yellow/Brown variety)
Chert (SiO2)
Category
Browse sedimentary rock (technically a variety of chalcedony) specimens identified by the Rock Identifier community.
Chert (Yellow/Brown variety)
Chert (SiO2)
Agate
Chalcedony (cryptocrystalline quartz)
Red Sandstone
Arenite (with Iron Oxide / Hematite cementation)
Blue Chalcedony
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Chalcedony (Botryoidal)
Silicon Dioxide (SiO2)
Crazy Lace Agate
Chalcedony (Silicon Dioxide, SiO2)
Blue Chalcedony
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Metaconglomerate
Metaconglomerate (Quartzite conglomerate)
Quartz
Quartz (Silicon Dioxide, SiO2)
Clear Quartz (Rock Crystal)
Quartz (SiO₂)
Vesicular Basalt with Quartz/Chalcedony
Vesicular Basalt (primarily Plagioclase, Pyroxene, and Olivine with SiO2 infill)
Amethyst Geode (Thunderegg)
Silicon Dioxide (SiO2) - Quartz Variety: Amethyst
Chert or Flint (polished/water-worn)
Chert (a microcrystalline or cryptocrystalline variety of quartz, SiO2). Flint is a specific variety of chert.
Quartz
Quartz (SiO₂)
Quartz
Quartz (SiO₂)
Moss Agate
Chalcedony (SiO2) with inclusions of manganese or iron oxides
Bumblebee Jasper
Fossiliferous Volcanic Rock (composed of Calcium Carbonate, Manganese Oxides, and Arsenic Sulfides)
Chalcedony with inclusions (Agate/Quartz)
Silicon Dioxide (SiO2)
Sandstone or Limestone
Sedimentary Rock
Tiger's Eye
Tiger's Eye (a variety of Chalcedony, which is cryptocrystalline quartz). Chemical Formula: SiO2 with inclusions of crocidolite fibers.
Chert / Flint
Chert (varieties include Flint)
Quartz
Silicon dioxide (SiO2)
Thunderegg
Agate-filled Rhyolitic Nodule (SiO2)
Orca Agate (Blue Chalcedony)
Silicon Dioxide (SiO2)
Blue Chalcedony
Silicon Dioxide (SiO2)
Carnelian (Chalcedony)
Silicon Dioxide (SiO2) with Iron Oxide impurities
Carnelian Agate Nodule
Silicon Dioxide (SiO2) - Carnelian Chalcedony
Dendritic Agate
Chalcedony (SiO2) with manganese/iron oxide inclusions
Carnelian
SiO2 (Microcrystalline Quartz / Chalcedony)
Chalcedony Nodule (Carnelian/Agate)
Chalcedony (Silicon Dioxide, SiO2)
Montana Moss Agate
Chalcedony (Silicon Dioxide, SiO2)
Agate Geode
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Quartz (Pebble)
Quartz (SiO₂)
Blue Lace Agate (Geode/Druzy variant)
Chalcedony (SiO2) with Quartz druzy
Chalcedony / Agate
Silicon Dioxide (SiO2)
Botryoidal Chalcedony
Silicon Dioxide (SiO2)
African Turquoise (Jasper)
Polychrome African Jasper (often marketed as 'African Turquoise' due to its color, but it is not true turquoise)
Fossiliferous Limestone (Coquina / Shell Limestone)
CaCO3 (Calcium Carbonate)
Chert / Pink Chert
Silicon Dioxide (SiO2)
Banded Gneiss (River Rock/Pebble)
Gneiss (specifically a banded variety often found as a river rock)
River Rocks (Black)
Various lithologies (e.g., basalt, chert, obsidian for black varieties), mechanically rounded clasts
Sandstone
Sandstone (various mineral compositions)