Chert (Nodule)
Microcrystalline or Cryptocrystalline Silica (SiO2)
sedimentary
Category
Not A Rock
Browse not a rock specimens identified by the Rock Identifier community.
Bauxite / Iron-rich Laterite
Laterite (principally Al(OH)3, Fe2O3, and SiO2)
sedimentary
Sandstone with Quartz Veins
Arenite (primarily SiO2 with Fe2O3 staining)
sedimentary
Northern Shoveler Duck (Note: This is a biological specimen, not a rock)
Spatula clypeata
not a rock (biological/ornithological)
Sandstone (specifically Banded Sandstone)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Chert Geode or Nodule
Microcrystalline Quartz (SiO2)
sedimentary
Druzy Quartz Geode (Oco or Moroccan variety)
Silicon Dioxide (SiO2)
mineral
Red Siltstone (or Red Shale)
Clastic Sedimentary Rock (Composition: primarily Quartz, Clay minerals, and Hematite Fe2O3)
sedimentary
Basalt (Amygdaloidal)
Amygdaloidal Basalt
igneous
Sandstone (Iron-stained)
Arenite (composed primarily of SiO2 with Fe2O3 staining)
sedimentary
Fossiliferous Sandstone (with Brachiopod or Bivalve mold)
Clastic Sedimentary Rock with Macrofossil Mold
sedimentary
Gneiss
Foliated Metamorphic Rock (Gneiss)
metamorphic
Gneiss
Gneissic Metamorphic Rock (Mineral composition: Quartz, Feldspar, Amphibole/Biotite)
metamorphic
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Granite Cobble
Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Mica)
igneous
Basalt with Plagioclase Feldspar
Basalt (mafic extrusive igneous rock) with plagioclase feldspar phenocrysts
Igneous
Banded Agate (Polished Slice)
Chalcedony (cryptocrystalline Quartz), SiO2
mineral
Agate
Silicon Dioxide (SiO2)
mineral
Massive Quartz with Host Rock
Silicon Dioxide (SiO2)
mineral
Chalcedony (Agate)
Silicon Dioxide (SiO2)
mineral
Sandstone with Quartz Vein
Arenite with SiO2 intrusion
sedimentary
Gneiss (High-Grade Metamorphic Rock)
Gneiss (primarily composed of Quartz, Feldspar, and Mica/Amphiboles)
metamorphic
Basalt with Quartz Veining
Basalt (Mafic Extrusive Igneous Rock) with SiO2 (Silicon Dioxide) veins
igneous
Quartz Druzy Geode
Silicon Dioxide (SiO2) - Crystalline Variety
mineral
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
mineral
Boxwork Quartz / Septarian Jasper
Boxwork (SiO2 with iron oxide inclusions)
metamorphic
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Granite
Granite
Igneous
Sandstone or Limestone
Arenite or Calcareous Sedimentary Rock
Sedimentary
Gneiss
Gneiss
metamorphic
White Marble
Recrystallized Calcite (CaCO3)
metamorphic
Serpentinite
Serpentinite (composed primarily of minerals in the Serpentine group)
metamorphic
Banded Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Sandstone (Greywacke)
Arenite / Wacke (Mainly SiO2 with various lithic fragments)
sedimentary
Basalt with Quartz/Calcite Vein
Amygdaloidal Basalt (matrix) with Mineral Vein filling
igneous
Sandstone
Arenite (SiO2 predominantly)
sedimentary
Mexican Crazy Lace Agate
Silicon Dioxide (SiO2) with iron and aluminum inclusions
mineral
Sandstone
Arenite (SiO2 based with various mineral cements)
sedimentary
Quartz Crystal (specifically a Double-Terminated variety)
Silicon Dioxide (SiO2) - Low Quartz
mineral
Quartz in Host Rock
Silicon Dioxide (SiO2) in Rhyolite or Granite matrix
igneous
Amphibolite
Amphibolite
metamorphic
Thunderegg (Ate Agate/Jasper Geode)
Silicon Dioxide (SiO2) within Rhyolite/Perlite matrix
sedimentary/igneous intermediary