Petrified Wood
Silicified Wood (primarily SiO2)
Category
Browse sedimentary rock (technically a microcrystalline quartz mineral aggregate) specimens identified by the Rock Identifier community.
Petrified Wood
Silicified Wood (primarily SiO2)
Ironstone (likely Limonite or Goethite)
Ferruginous sedimentary rock (FeO(OH)·nH2O)
Sandstone (likely Arkose or Quartz Sandstone)
Arenite (SiO2 principal component)
Shale
Shale
Red Sandstone (Old Red Sandstone)
Ferruginous Sandstone (SiO2 + Fe2O3)
Quartzite Pebble
SiO2 (Silicon Dioxide)
Slate
Foliated Metamorphic Rock (Mainly composed of Quartz, Illite, Chlorite)
Quartz Pebbles
Silicon Dioxide (SiO2)
Jasper (Iron-stained Chert)
Silicon Dioxide (SiO2)
Quartzite pebble
Quartzite (SiO2)
Quartzite Pebble
Quartzite (predominantly Silicon Dioxide - SiO2)
Basalt
Mafic Volcanic Rock (composed of Plagioclase Feldspar and Pyroxene)
Gneiss (Metamorphic Rock)
Gneiss (variable mineral formula primarily containing Quartz, Feldspar, and Mica)
Ferruginous Quartz
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Quartz Vein in Host Rock (Gneiss/Schist)
Silicon Dioxide (SiO2) within a metamorphic matrix
Quartzite
Quartzite (primarily SiO2)
Granite (Pink/Red)
Phaneritic Igneous Rock (Rich in K-Feldspar)
River Quartzite Pebble
Quartzite (SiO2)
Chert
Silicon dioxide (SiO2)
Chert (often called Flint in this variation)
Silicon dioxide (SiO2) - Microcrystalline quartz
White Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Granite Pebble
Granite (composed mainly of Quartz, Feldspar, and Mica)
Carnelian
Carnelian (subset of Chalcedony); SiO2 with Iron Oxide impurities
Breccia
Clastic Breccia (SiO2/CaCO3 dominated)
Banded Agate (White Agate)
Chalcedony (Silicon Dioxide, SiO2)
Agate
Silicon Dioxide (SiO2) - Banded Chalcedony
Quartz Vein with Iron Staining
Silicon Dioxide (SiO2)
Gneiss
Gneiss (High-grade regional metamorphic rock)
Green Onyx (Banded Calcite)
Travertine (CaCO3 - Calcium Carbonate)
Milky Quartz with Chlorite/Mica inclusions
Silicon Dioxide (SiO2) with inclusions
Sandstone (with Liesegang rings or Oxidation)
Arenite (primarily Quartz SiO2 with Iron Oxide Fe2O3 staining)
Quartzite Pebble
Quartzite (SiO2)
Chalcedony (specifically Agate or Flint)
Silicon Dioxide (SiO₂)
Gneiss
Gneiss (High-grade Metamorphic Rock)
Quartz Pebble
Silicon Dioxide (SiO2)
Iron-Stained Quartz (Riverside Cobble)
Silicon Dioxide (SiO2) with Limonite/Hematite inclusions
Red Sandstone (Iron-rich)
Ferruginous Sandstone (variable formula, primarily SiO2 + Fe2O3)
Quartzite River Rock
Quartzite (primarily SiO2)
Chalcedony Geode
Chalcedony (SiO2) within a geode structure
Granite (Dioritic or Hornblende-rich)
Phaneritic Plutonic Felsic to Intermediate Igneous Rock
Sandstone
Arenite
Milky Quartz with Iron Inclusions
Silicon Dioxide (SiO2)