Gneiss
Gneiss (High-grade metamorphic rock)
Category
Browse not a rock or mineral specimens identified by the Rock Identifier community.
Gneiss
Gneiss (High-grade metamorphic rock)
Granite
Granite (Phaneritic Acid Igneous Rock)
Schist
Mica Schist (primarily Muscovite and Quartz)
Green Aventurine
Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)
Sandstone (with biological crust)
Arenite (SiO2 based)
Quartz Geode
Silicon Dioxide (SiO2)
Sandstone (Quartz-rich Pebble)
Arenite (primarily SiO2)
Sandstone (Red/Brown Variety)
Arenite (composed primarily of SiO2 with Fe2O3 iron oxide inclusions)
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily Quartz with Limonite/Goethite staining)
Citrine (Heat-treated Amethyst)
Citrine Quartz (SiO2)
Quartz (Milky or Common Quartz)
Silicon Dioxide (SiO2)
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron inclusions)
Gneiss
Gneiss (High-grade metamorphic rock typically composed of Quartz, Feldspar, and Mica/Amphibole)
Feldspathic Granite (likely Syenite or Granite Pegmatite)
Phaneritic Acidic Igneous Rock (KAlSi3O8 dominant with SiO2)
Granitic Gneiss
Gneiss (Polymetamorphic Granitic Gneiss)
Granitic Pegmatite
Coarse-grained Igneous Rock (Granitic composition: KAlSi3O8, SiO2)
Amygdaloidal Basalt
Amygdaloidal Basalt (containing secondary minerals like Quartz, Zeolites, or Calcite)
Basalt
Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)
Conglomerate
Conglomerate (Clastic Sedimentary Rock)
Almandine Garnet in Schist Matrix
Almandine - Fe3Al2(SiO4)3
Gneiss
Gneiss (High-grade regional metamorphic rock)
Mica Schist
Muscovite/Biotite Schist
Granite
Phaneritic Acidic Igneous Rock (Granite)
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Sandstone (Ferruginous)
Arenite (iron-rich)
Quartz Geode
Silicon Dioxide (SiO2) in a Geode body
Red Sandstone
Clastic sedimentary rock (primarily Quartz and Feldspar with Iron Oxide cement)
Ferruginous Quartz
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
Milky Quartz
Quartz (Silicon Dioxide - SiO2)
Dyed Agate
Silicon Dioxide (SiO2) with artificial pigment
Amethyst
SiO2 (Silicon Dioxide with Iron impurities and natural radiation influence)
Tree Agate
Dendritic Agate (Silicon Dioxide, SiO2 + Manganese/Iron oxides)
Smoky Quartz (Tumbled)
Silicon Dioxide (SiO2)
Pink Tumbled Agate (Dyed)
Silicon Dioxide (SiO2) with artificial dyes
Agate
Agate (Microcrystalline Quartz, SiO2)
Yellow Quartz (Citrine or Iron-stained Quartz)
Silicon Dioxide (SiO2)
Amethyst Geode
Silicon Dioxide (SiO2) - Amethyst variety of Quartz
Green Aventurine
Quartz variety (SiO2 with inclusions)
White Jade / White Chalcedony
Nephrite Jade (Ca2(Mg,Fe)5Si8O22(OH)2) or Chalcedony (SiO2)
Sandstone
Sandstone (lithified sand)
Basalt (Crushed Stone Aggregate)
Mafic Volcanic Basalt (Major Minerals: Plagioclase Feldspar, Pyroxene, Olivine)
Quartzite River Rock with Dendrites
Metamorphosed Quartz-rich Sandstone with Manganese Oxide (MnO2) inclusions