Note regarding image quality
Category
Not A Rock
Browse not a rock specimens identified by the Rock Identifier community.
Quartz Geode
Silicon Dioxide (SiO2)
Sandstone (likely Arkosic or Lithic Sandstone)
Clastic Sedimentary Rock (SiO2 with assorted minerals)
Basalt
Basalt (Mafic Extrusive Rock)
Conglomerate
Conglomerate (clastic sedimentary rock)
Sandstone (Quartzite-rich)
Clastic Sedimentary Rock (primarily SiO2)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Sandstone (likely Arkose or Quartz Sandstone)
Clastic sedimentary rock (primarily SiO2)
Banded Agate
Chalcedony / Silicon Dioxide (SiO2)
Gossan with Copper Carbonate (Chrysocolla/Malachite)
Ferruginous Oxide (Gossan) with Cu2CO3(OH)2 (Malachite) or (Cu,Al)2H2Si2O5(OH)4 (Chrysocolla)
Basalt with Quartz/Feldspar Inclusion
Basalt (containing Silicate minerals such as SiO2 and (Ca,Na)(Al,Si)4O8)
Granite River Pebble
Phaneritic Felsic Igneous Rock (Granite)
Basalt
Basalt (Mafic volcanic rock)
Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
Milky Quartz with Iron Inclusions
Silicon Dioxide (SiO2)
Epidote
Epidote Group (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
Blue Howlite (Dyed)
Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)
Jasper Breccia
Silicon Dioxide (SiO2) with impurities
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Quartz (Milky or Cloudy variety)
Silicon Dioxide (SiO2)
Picture Jasper
Silicon Dioxide (SiO2)
River Pebbles (Stream-rounded rocks)
Fluvial Detritus (varied mineralogy)
Chert (Chert Pebble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Coquina Jasper
Fossiliferous Chalcedony (SiO2)
Labradorite (Larvikite variety)
Plagioclase Feldspar (Na,Ca)(Al,Si)4O8 with Monzonite/Syenite matrix
Sandstone Concretion
Septarian or Carbonate-cemented Sandstone Concretion
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
Ironstone Concretion
Limonitic/Hematitic Concretion
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
Milky Quartz
Silicon Dioxide (SiO2)
Sandstone (likely River-tumbled Picture Sandstone)
Arenite (predominantly SiO2 with iron oxide impurities)
Quartzite
Quartzite (primarily SiO2)
Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Dyed Agate
Chalcedony (Silicon Dioxide, SiO2)
Bumblebee Jasper
Volcanic Tuff (mixture of Quartz, Sulfur, Hematite, and Orpiment)
Sand Dollar Fossil
Echinoidea (Clypeasteroida)
Coral Fossil (Favosites type)
Phylum Cnidaria, Class Anthozoa (often CaCO3 - Calcium Carbonate)
Quartz with Limonite Staining
Silicon Dioxide (SiO2) with Hydrated Iron Oxide (FeO(OH)·nH2O)
Garnet in Matrix (Eclogite)
Eclogite, featuring Almandine or Pyrope Garnet [X3Y2(SiO4)3]
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock including secondary mineral infills)
Amethyst (Agate/Chalcedony variety)
Silicon Dioxide (SiO2) with iron impurities