Basalt (Polished River Stone)
Mafic Volcanic Rock (primarily Plagioclase and Pyroxene)
Category
Browse rock specimens identified by the Rock Identifier community.
Basalt (Polished River Stone)
Mafic Volcanic Rock (primarily Plagioclase and Pyroxene)
Chert (Jasper variation)
Silicon Dioxide (SiO2)
Basalt (Weathered/River worn)
Mafic Volcanic Rock (Primarily Plagioclase Feldspar and Pyroxene)
Porphyritic Basalt with Quartz Inclusions
Aphanitic Porphyritic Basalt
Granodiorite Pebble
Granodiorite (containing Quartz, Plagioclase Feldspar, and Biotite/Amphibole)
Basalt (Road Gravel)
Aphanitic mafic volcanic rock (various compositions of plagioclase feldspar and pyroxene)
Basalt
Mafic Volcanic Rock (composed of plagioclase, pyroxene, and olivine)
Basalt
Basalt
Limestone with Calcite Veins
Sedimentary Calcium Carbonate (CaCO3)
Serpentinite
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4
Basalt
Basalt (composition of Plagioclase feldspar, Pyroxene, and Olivine)
Basalt River Stone
Basalt
Basalt
Basalt
Banded Agate (specifically Lake Superior Agate)
Silicon dioxide (SiO2) - Cryptocrystalline Chalcedony
Basalt River Stone
Extrusive Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)
Pink Granite
Phaneritic Felsic Igneous Rock (composed primarily of K-feldspar, Quartz, and Biotite)
Basalt Pebble
Extrusive mafic igneous rock; primarily (Ca, Na)(Mg, Fe, Al)Si2O6 and (Ca, Na)AlSi3O8
Unakite (Tumbled)
Epidotized Granite
Basalt (Gravel Pebble)
Basalt (contains pyroxene, plagioclase feldspar, and olivine)
Andesite River Stones
Andesite
Basalt
Basalt (predominantly Plagioclase Feldspar and Pyroxene)
Vesicular Basalt
Extrusive mafic igneous rock (primarily Plagioclase Feldspar and Pyroxene)
Pink Granite
Granite (Phaneritic intrusive igneous rock dominated by Quartz and K-Feldspar)
Basalt
Basalt (composition of plagioclase feldspar, pyroxene, and olivine)
Basalt with Plagioclase Phenocrysts
Porphyritic Basalt
Granite Tile (Commercial Granite)
Granite (Phaneritic Quartz-Feldspar Plutonic Rock)
Limonitic Quartzite
Metamorphosed sandstone with Limonite (FeO(OH)·nH2O) staining
Granite
Granite
Unakite
Epidotized Granite
Serpentine
Serpentine-group (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4
Granite
Intrusive igneous rock (SiO2 range 65-75%)
Basalt with Iron Oxidation
Mafic Igneous Basalt
Basalt Pebble
Basalt
Basalt with Porphyritic Texture
Porphyritic Basalt
Basalt (River Stone)
Basalt
Quartzite with Quartz Vein
Quartzite (primarily SiO2)
Basalt (River Pebble)
Basalt
Sandstone
Arenite (primarily SiO2)
Pink Granite
Phaneritic Plutonic Rock (Granite with K-Feldspar)
Granodiorite (Riverbed Cobble)
Granodiorite
Basalt River Pebble
Extrusive mafic igneous rock; primarily composed of Plagioclase Feldspar and Pyroxene
Chert (specifically Flint or Jasper variant)
Microcrystalline Quartz (SiO2)