Chert (varietal: Jasper or Flint likely, but definitive identification is difficult from image)
SiO₂ (silicon dioxide)
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.
Chert (Grey/Black variety)
Chert (Silicon Dioxide, SiO2)
sedimentary
Chert / River Pebble
Microcrystalline Silica (SiO2)
sedimentary
Jasper (specifically Polychrome or Desert Jasper)
Silicon Dioxide (SiO2) with impurities
sedimentary or igneous-associated mineral
Garnet (Red Garnet)
Garnet Group. The red varieties seen in jewelry are typically Almandine (Fe3Al2(SiO4)3), Pyrope (Mg3Al2(SiO4)3), or a mix of the two (pyrope-almandine series).
Mineral (specifically, a variety of the mineral species Pyrope-Almandine Garnet)
Jasper (specifically Bloodstone or Heliotrope variety)
Silicon Dioxide (SiO2) with iron oxide inclusions
Sedimentary / Mineral
Picture Jasper
Silicon Dioxide (SiO2) - Opaque Impure Chalcedony
sedimentary
Precious Opal in Matrix
Hydrated Silica (SiO2·nH2O)
mineral
Gneiss
Gneiss (High-grade regional metamorphic rock)
metamorphic
Pink Dyed Agate (Pink Agate Slice)
Silicon Dioxide (SiO2) - Chalcedony / Cryptocrystalline Quartz
mineral
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Red Jasper
Jasper (a variety of Chalcedony, SiO₂)
Mineraloid (cryptocrystalline quartz)
Siltstone
Siltstone (primarily SiO2, Al2O3)
sedimentary
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Banded Agate (specifically Lake Superior Agate style)
Silicon Dioxide (SiO2) - Chalcedony variety
mineral
Asphalt Concrete (Bituminous Concrete)
Bituminous aggregate
sedimentary
Serpentinite
Serpentinite (complex silicate minerals including lizardite, chrysotile, and antigorite: (Mg,Fe)3Si2O5(OH)4)
metamorphic
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Banded Agate (specifically Moss or River Agate variety)
Cryptocrystalline Quartz (SiO2)
mineral
Unakite
Epidotized Granite
metamorphic
Laterite
Laterite (no specific mineral formula as it's a rock type)
Sedimentary
Chert / Flint
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Amber
Succinite (specifically for Baltic amber); approximate formula C10H16O
organic mineraloid
Banded Chert or Chert with Quartz Veins
Chert (SiO2)
Sedimentary
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Amber (specifically Cherry Amber)
Succinite (with the chemical formula C10H16O)
Organic Gemstone (not a mineral)
Quartz
Quartz (SiO2 - Silicon Dioxide)
Mineral
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Granite (specifically Red Granite)
Phaneritic Plutonic Rock (High in Alkali Feldspar and Quartz)
igneous
Ferruginous Quartz (Iron-stained Quartz)
Silicon Dioxide (SiO2) with Hematite/Goethite inclusions
mineral
Limonite-stained Quartz / Quartzite
Silicon Dioxide (SiO2) with iron hydroxides (FeO(OH)·nH2O)
sedimentary or metamorphic
Chert (Nodule / Geode fragment)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (specifically Flint or Common Chert)
Chert (Cryptocrystalline Silica, SiO2)
sedimentary
Chert (specifically Yellow or Brown Chert / Jasper)
Silicon Dioxide (SiO2)
sedimentary
River Pebble (likely Quartzite or Chert)
Silicon Dioxide (SiO2) crystal conglomerate
sedimentary or metamorphic
Gneiss
Gneiss (High-grade regional metamorphic rock)
metamorphic
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Chert (specifically Jasper/Carnelian Agate)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (specifically Flint or Jasper variant)
Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)
sedimentary
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
sedimentary
Red Sandstone
Arenite (Ferruginous Sandstone)
sedimentary
Coquina
Coquina (a type of limestone)
Sedimentary