Laterite
Laterite (primarily composed of hydrated oxides of iron and aluminum)
Sedimentary Rock (as a residual soil/rock, it's often considered a type of sedimentary rock due to its formation from weathering, though it can cross into soil science)
Category
Metamorphic (Likely Gneiss Or Schist Based On Texture)
Browse metamorphic (likely gneiss or schist based on texture) specimens identified by the Rock Identifier community.
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Quartzite Cobble
Quartzite (principally SiO2)
metamorphic
River Pebble (likely Quartzite or Quartz)
Quartzite (SiO2)
metamorphic
Vesicular Basalt
Basalt (SiO2 range 45-52%) with vesicular texture
igneous
River Cobble (likely Quartzite)
Metamorphosed Sandstone (SiO2)
metamorphic
Green Aventurine
SiO2 (Silicon Dioxide with inclusions of Fuchsite)
mineral
Black Tourmaline (Schorl)
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
mineral
Ruby
Corundum (Al2O3 with Chromium traces)
mineral
Green Aventurine
Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2 + K(Al,Cr)2AlSi3O10(OH)2
mineral
Aquamarine
Beryl (Be3Al2Si6O18 with Fe2+ impurities)
mineral
Aventurine
Quartz with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)
mineral
Chrysoberyl (Cyclic Twin)
Beryllium Aluminum Oxide (BeAl2O4)
mineral
Quartzite with Calcite Accretion
Metamorphosed Quartz Sandstone (SiO2 with CaCO3 coating)
metamorphic
Petrified Wood
Silicified Wood (primarily SiO2)
metamorphic
Corundum (Sapphire in Host Rock)
Corundum (Aluminum Oxide, Al2O3)
mineral
Sandstone Cobble
Arenite (Secondary classification based on grain size)
sedimentary
Native Gold (in the form of jewelry)
Gold (Au)
mineral
Petrified Wood (Silicified Wood)
Silicified Paleoflora (mainly Quartz, SiO2)
metamorphic
Quartz (Common or Milky)
Silicon Dioxide (SiO2)
mineral
Agate
Agate (a cryptocrystalline variety of Quartz, SiO₂)
Mineral
Milky Quartz with Iron Oxide Staining
Quartz (Silicon Dioxide, SiO2)
mineral
Quartz-rich pegmatite, possibly with mica and feldspar
Granitic pegmatite; mainly quartz (SiO₂), feldspar, and biotite/muscovite mica
igneous
Likely basaltic rock fragment
Fine-grained mafic igneous rock, probably basalt (plagioclase–pyroxene ± olivine)
igneous
Fuchsite in Quartz
K(Al,Cr)2(AlSi3O10)(OH)2 + SiO2
metamorphic
Greenstone
Chlorite schist or metabasalt depending on specific composition
Metamorphic
Green Aventurine
Silicon Dioxide (Quartz) with Fuchsite inclusions (SiO2)
mineral
Emerald
Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)
gemstone
Emerald
Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities
gemstone
Yellow Beryl (Heliodor)
Beryllium aluminum silicate (Be3Al2Si6O18)
mineral
Black Tourmaline
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
mineral
Rounded dark-gray pebble, likely basalt or andesite
Fine-grained mafic to intermediate volcanic rock; commonly plagioclase ± pyroxene, amphibole, and minor olivine
igneous
Likely serpentine pebble
Serpentinite; predominantly serpentine-group minerals, Mg₃Si₂O₅(OH)₄
metamorphic
Chert / Quartz Pebble
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Weathered basaltic cobble
Altered basalt, predominantly plagioclase and pyroxene
igneous
Quartzite with inclusions or weathered surface
Quartzite
metamorphic
Weathered basalt or iron-rich river cobble
Basalt, likely with iron-oxide staining; exact identification requires testing
igneous
Calcite (or Alabaster, if truly carved)
Calcium Carbonate (CaCO3)
Mineral/Rock
Fuchsite in Quartz
Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2) in Quartz (SiO2)
metamorphic
Basaltic volcanic pebble
Fine-grained mafic igneous rock, chiefly plagioclase and pyroxene, commonly with olivine and iron-titanium oxides
igneous
Slate
Foliated Metamorphic Rock (primarily composed of quartz, illite, chlorite, and micas)
metamorphic
Sandstone
Sedimentary Rock (Quartz arenite / Lithic sandstone)
sedimentary
Green Tourmaline
Elbaite (Na(Li,Al)3Al6(BO3)3Si6O18(OH)4)
mineral