Unidentified Rock Fragment
Unknown
Category
Browse sedimentary (secondary formation) specimens identified by the Rock Identifier community.
Unidentified Rock Fragment
Unknown
Banded Chert with Quartz Veining
Microcrystalline Quartz (SiO2)
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Oyster Shell (Aragonite/Calcite)
Calcium Carbonate (CaCO3)
Limestone with Calcite Veining
Calcium Carbonate (CaCO3)
Ferruginous Sandstone (Gritstone)
Arenite with Iron-Oxide Cement (SiO2 with Fe2O3 and FeO(OH))
Chalk (Calcitic)
Calcium Carbonate (CaCO3) - Biogenic Sedimentary Rock
Red Chert
Microcrystalline Quartz (SiO2)
Ferruginous Sandstone
Sandstone with iron oxide (Hematite/Limonite) cement
Agate (translucent pebble)
Silicon dioxide (SiO2) - Microcrystalline Quartz
Sandstone
Arenite (primarily SiO2)
Sandstone (Quartzose Sandstone)
Arenite (SiO2 principal component)
Sandstone
Arenite (composed primarily of SiO2)
Yellow Jasper (Limonite-stained Chert)
Silicon Dioxide (SiO2) with Limonite/Goethite inclusions
Chert (Jasper variety)
Silicon Dioxide (SiO2)
Yellow Jasper
Silicon Dioxide (SiO2) with iron hydroxides (Goethite/Limonite)
Zebra Jasper
Tumbled Opaque Chalcedony (SiO2)
Banded Agate
Cryptocrystalline Quartz (SiO2)
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
Sandstone (Quartzose type)
Arenite (primarily SiO2)
Petrified Dinosaur Bone (Gembone)
Agatized Dinosaur Bone
Mookaite Jasper
Radiolarite (Silicon Dioxide, SiO2)
Ferruginous Quartz (Iron-stained Quartzite)
Silicon Dioxide (SiO2) with iron oxide inclusions
Agate Geode
Cryptocrystalline Quartz (SiO2)
Fluorite
Fluorite (Calcium Fluoride - CaF2)
Limonite (Iron Ore)
Limonite (Hydrated Iron Oxide, FeO(OH)·nH2O)
Sandstone
Arenite (primarily SiO2)
Mookaite Jasper
Silicified Radiolarite (SiO2)
Jasper with Quartz inclusion
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
Sandstone with Liesegang Rings
Arenite with Iron Oxide Concretions
Greywacke (Briarcliff Schist/Gneiss)
Manhattan Schist / Fordham Gneiss complex
Chert (Banded)
Microcrystalline Quartz (SiO2)
Sandstone (Ferruginous)
Arenite (composed primarily of SiO2 with iron oxide Fe2O3 cement)
Mookaite Jasper
Silicified Radiolarite (SiO2 with iron impurities)
Milky Quartz (Vein Quartz)
Silicon Dioxide (SiO2)
Orange Calcite
Calcium Carbonate (CaCO3)
Coprolite
Coprolite
Chert
Microcrystalline silica (SiO2)
Milky Quartz Geode or Druzy Quartz
Silicon Dioxide (SiO2)
Chert / River Pebble
Silicon Dioxide (SiO2)
Chert (varietal: Jasper or Flint likely, but definitive identification is difficult from image)
SiO₂ (silicon dioxide)