Chalcedony (Agate/Chert)
Silicon Dioxide (SiO₂)
mineral
Category
Sedimentary (Cryptocrystalline Quartz)
Browse sedimentary (cryptocrystalline quartz) specimens identified by the Rock Identifier community.
Carnelian
Carnelian (Silicon Dioxide - SiO2 with Hematite impurities)
Mineral
Puddingstone
Conglomerate
Sedimentary
Ferruginous Quartz
Quartz (Silicon Dioxide, SiO2) with iron oxide inclusions
mineral
Chert / Red Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Chert (specifically Flint or Common Opal/Chalcedony mix)
Microcrystalline Quartz (SiO2)
sedimentary
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Turquoise
Hydrated phosphate of copper and aluminum - CuAl6(PO4)4(OH)8·4H2O
mineral
Ferruginous Quartz (Iron-stained Quartz)
Silicon Dioxide (SiO2) with Iron Oxide inclusions (Fe2O3)
mineral
Carnelian Agate
Carnelian (Silicon Dioxide: SiO2) with iron oxide impurities
mineral
Geode (Unopened)
Silica-lined Vug (primarily SiO2)
sedimentary
Jasper
Silicon dioxide (SiO2) with iron oxide inclusions
sedimentary
Carnelian
Carnelian (a variety of Chalcedony, SiO₂)
Mineral
Geode (Quartz)
Silicon Dioxide (SiO2)
mineral
Chert Pebble
Microcrystalline Quartz (SiO2)
sedimentary
Concretion with Quartz Veining
Septarian Concretion (CaCO3 / SiO2)
sedimentary
Quartz (Drusy/Crystalline)
Silicon Dioxide (SiO2)
mineral
Chalcedony (Agate/Jasper mix in host rock)
Chalcedony (cryptocrystalline Silicon Dioxide, SiO2)
mineral
Carnelian Agate
Silicon dioxide (SiO2) - variety of Chalcedony
mineral
Concretion or Geode (unbroken)
Varied (depending on mineral composition and cementing agent). For quartz-lined geodes, the scientific name of the dominant mineral would be Quartz (SiO2). For calcite-lined geodes, Calcite (CaCO3). Concretions are often composed of cryptocrystalline quartz (chert), calcite, or iron oxides.
Sedimentary rock (specifically a concretion or possibly a geode)
Blue Chalcedony and Picture Jasper Beads
Blue Chalcedony (SiO2), Picture Jasper (SiO2)
Mineral
Quartz (Milky/Crystalline variety)
Silicon Dioxide (SiO2)
mineral
Epidote in Quartz
Quartz with Epidote inclusions (SiO2 with Ca2(Al,Fe)3(SiO4)3(OH) inclusions)
Mineral
Quartz on Sandstone
Silicon Dioxide (SiO2) in Lithic Sandstone
sedimentary
Quartz
Silicon Dioxide (SiO2)
Mineral
Wonderstone
Rhyolite (Silicon Dioxide with Iron Oxide impurities)
igneous
Quartz Crystal Fragment
Silicon Dioxide (SiO2)
mineral
Dinosaur Fossil (Skull)
Dinosauria fossilis (Petrified Hydroxyapatite / Calcium Carbonate)
sedimentary
Sandstone with trace fossil
Sandstone, possibly with Skolithos or similar trace fossil
sedimentary
Sandstone (Quartzite-rich)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Quartz (variety of colors)
SiO2 (Silicon Dioxide)
Mineral
Sandstone (Ferruginous)
Arenite with Iron Oxide (Fe2O3) cement
sedimentary
Chert (Flint variety)
Microcrystalline Silica (SiO2)
sedimentary
Iron-stained Quartz (with Limonite/Hematite)
Silicon Dioxide (SiO2) with Iron Oxide inclusions (FeO(OH) or Fe2O3)
Mineral
Chalcedony (Common Opal/Chert variety)
Silicon Dioxide (SiO2)
mineral
Sandstone
Clastic Sedimentary Rock (composed mostly of quartz, SiO2)
sedimentary
White Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Ferruginous Quartz
Silicon Dioxide (SiO2) with iron oxide inclusions
mineral
Specular Hematite with Quartz and Limonite
Hematite (Fe2O3) with Quartz (SiO2) and Limonite (FeO(OH)·nH2O)
Mineral
Quartz (Milky or White Quartz)
Silicon Dioxide (SiO2)
mineral