Banded Gneiss
Gneiss (Metamorphic Rock)
Category
Browse mineral like byproduct (often mistaken for igneous rock or meteorite) specimens identified by the Rock Identifier community.
Banded Gneiss
Gneiss (Metamorphic Rock)
Granite
Granite
Serpentinite
Serpentinite (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4
Banded River Rock / Gneiss (highly weathered)
Gneiss
Scoria (Red Lava Rock)
Scoria (Vesicular Basalt/Andesite)
Sandstone
Arenite
Calcite Geode
Calcium Carbonate (CaCO3)
Sandstone (Quartzose)
Arenite (primarily SiO2)
Mahogany Obsidian
Volcanic Glass (predominantly SiO2 with inclusions of Hematite or Magnetite)
Basalt (Vesicular or Porphyritic)
Basalt (composed primarily of plagioclase feldspar, pyroxene, and olivine)
Amethyst (as a jewelry accent)
Amethyst (Silicon Dioxide SiO2 with Iron impurities)
Yellow Quartzite (Beach Pebble)
Quartzite (primarily SiO2)
Epidote
Epidote Group (e.g., Clinozoisite, Epidote, Piemontite), Epidote formula: Ca2(Al,Fe)3(SiO4)3(OH)
Turquoise and Hematite
CuAl6(PO4)4(OH)8·4H2O (Turquoise) and Fe2O3 (Hematite)
Basalt (Beach Pebble)
Basalt (Aphanitic Mafic Igneous Rock)
Granite
Granite (Mainly Quartz SiO2 and Feldspar KAlSi3O8)
Sunstone
Oligoclase or Andesine (Plagioclase Feldspar) - (Ca, Na)((Al, Si)2Si2O8)
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide, SiO2)
Conglomerate
Conglomerate rock
Chert with Quartz/Calcite Vein
Microcrystalline Silica (SiO2)
Sandstone
Arenite
Basalt
Basalt (principally Plagioclase and Pyroxene)
Basalt with Plagioclase Phenocrysts
Porphyritic Basalt
Vesicular Basalt with Amygdaloidal Infill
Basalt (Mafic Extrusive Igneous Rock)
Quartz
Quartz (SiO₂ - Silicon Dioxide)
Chert (Chalcedony/Agate variety)
Silicon Dioxide (SiO2)
Granite
Plutonic felsic igneous rock
Green Schist
Greenschist (composed of Chlorite, Actinolite, and Epidote)
Diorite
Diorite (Intermediate intrusive igneous rock)
Granite
Phaneritic Plutonic Felsic Rock (SiO2 > 69%)
Sandstone (Quartzite-rich)
Clastic Sedimentary Rock (primarily SiO2)
Basalt
Basalt (Mafic volcanic rock)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Botryoidal Chalcedony (Desert Rose / Agate)
Silicon Dioxide (SiO₂)
Sandstone (likely Quartz Sandstone)
Arenite (SiO2 based)
Howlite and Purple Amethyst Druzy
Calcium Borosilicate Hydroxide (Howlite) and Silicon Dioxide (Quartz/Amethyst)
Sandstone (Ferruginous)
Arenite (Siliclastic Sedimentary Rock)
Rough Corundum (Sapphire/Ruby mixture)
Corundum (Aluminum Oxide, Al2O3)
Biotite / Black Mica
K(Mg,Fe)3(AlSi3O10)(F,OH)2
Sandstone Pebble
Arenite (primarily SiO2)
Andesite
Andesite (Intermediate Extrusive Volcanic Rock)
Quartz (specifically Milky or Clear Quartz fragment)
Silicon Dioxide (SiO2)