Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Category
Mineral (Native Element Alloy)
Browse mineral (native element alloy) specimens identified by the Rock Identifier community.
Quartz Geode (Nodule)
Silicon Dioxide (SiO2)
sedimentary or igneous
Sandstone with Concretions / Liesegang Rings
Arenite with iron oxide banding
sedimentary
Banded Rhyolite (likely Green Jasper/Agate variety)
Silicon Dioxide (SiO2) with mineral inclusions
igneous
Marble
Metamorphic rock composed of Recrystallized Carbonate Minerals (chiefly CaCO3)
metamorphic
Lepidolite
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)
mineral
Turquoise (Rough Specimens)
Hydrous phosphate of copper and aluminium - CuAl6(PO4)4(OH)8·4H2O
mineral
Sapphire (Raw/Rough)
Corundum (Al2O3)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Green Aventurine
Aventurine Quartz (SiO2 with Fuchsite inclusions)
mineral
Blue Apatite
Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)
mineral
Sandstone (Ferruginous)
Arenite (with Iron Oxides)
sedimentary
Lepidolite
K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2 (Lithium-bearing Phyllosilicate)
mineral
Red Sandstone
Sandstone (principally Quartz with Iron Oxide coating)
sedimentary
Red Sandstone
Arenite (primarily Quartz with Hematite cement)
sedimentary
Limonitic Sandstone (Stained Sandstone)
Clastic Sedimentary Rock with Iron Oxide (Limonite/Goethite) staining
sedimentary
Sandstone (with Iron Staining)
Clastic Sedimentary Rock (primarily Quartz, SiO2)
sedimentary
Red Sandstone (Hematitic)
Clastic sedimentary rock (SiO2 with Fe2O3 inclusions)
sedimentary
Sandstone (Ferruginous)
Arenite (with Goethite/Limonite cement)
sedimentary
Sandstone
Arenicola (comprising mostly Quartz, SiO2)
sedimentary
Quartz
Silicon Dioxide (SiO₂)
Mineral
Gossan (Iron Hat) with Quartz and Chlorite
Limonite/Goethite-rich Gossan (FeO(OH)·nH2O) with inclusions of Quartz and Chlorite
Mineral/Metamorphic Substrate
Quartz with mica and feldspar (Pegmatite fragment)
Granitic Pegmatite (composed mainly of SiO2 with KAlSi3O8)
igneous
Granite
Granite (Felsic Plutonic Rock)
igneous
Amethyst Geode
Silicon Dioxide (SiO2) with trace Iron (Fe3+) impurities
mineral
Travertine (Tufa)
Terrestrial Sedimentary Limestone (CaCO3)
sedimentary
Tiger's Eye
Silicon dioxide (SiO2) with fibrous inclusions of crocidolite (riebeckite)
Mineral
Fossilized Shark Tooth (Basal Bone)
Otodus sp. (Mineralized Hydroxyapatite)
sedimentary
Granite Cobble
Granite (Phaneritic Quartz-Feldspar Felsic Rock)
igneous
Dyed Agate
Chalcedony (Silicon Dioxide, SiO2)
mineral
Quartz (Crystal/Druzy Quartz)
Quartz (SiO₂)
Mineral
Prehnite
Prehnite, Ca2Al2Si3O10(OH)2
Mineral
Peach Moonstone
Orthoclase Feldspar (KAlSi3O8)
mineral
Herkimer Diamond
Quartz (Silicon Dioxide) - SiO2
mineral
Serpentinite
Serpentinite (composed primarily of serpentine-group minerals like antigorite, chrysotile, and lizardite; chemical formula varies but generally Mg3Si2O5(OH)4)
Metamorphic Rock
Milky Quartz with Iron Inclusions
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Green Fluorite
Calcium Fluoride (CaF2)
mineral
Moonstone
Orthoclase Feldspar (KAlSi3O8)
Mineral
Sandstone (likely Quartzose Sandstone)
Arenite (composed primarily of SiO2)
sedimentary
Gneiss (likely)
Gneiss
Metamorphic
Yellow Quartz (Citrine-colored Quartz Pebble)
Silicon Dioxide (SiO2)
mineral