Unidentified Rock Fragment
Unknown
Category
Browse metamorphic (likely gneiss or schist based on texture) specimens identified by the Rock Identifier community.
Unidentified Rock Fragment
Unknown
Sandstone (likely Greywacke or Lithic Sandstone)
Arenite / Wacke
Schist with Schorl (Black Tourmaline)
NaFe3Al6(BO3)3Si6O18(OH)4 (Schorl)
Water and Silt (Sedimentary Environment)
Suspended Sediment / H2O (dihydrogen monoxide)
Granite
Granite (Phaneritic Igneous Rock)
Ruby
Corundum (Al2O3 with Chromium traces)
Aquamarine
Beryl (Be3Al2Si6O18 with Fe2+ impurities)
Green Aventurine
Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2 + K(Al,Cr)2AlSi3O10(OH)2
Chrysoberyl (Cyclic Twin)
Beryllium Aluminum Oxide (BeAl2O4)
Coquina (Fossiliferous Limestone)
Coquina (Organic Clastic Limestone)
N/A (Non-Geological Specimen)
Slate
Slate (Foliated Metamorphic Rock)
Corundum (Sapphire in Host Rock)
Corundum (Aluminum Oxide, Al2O3)
Ruby
Corundum (Aluminum Oxide with Chromium traces), Al2O3:Cr
Raw Emerald
Beryl (Be3Al2(SiO3)6) with Cr/V impurities
Laterite
Lateritic Soil/Rock (rich in Fe2O3 and Al2O3)
Lepidolite (likely)
K(Li,Al)3(Al,Si)4O10(F,OH)2 (Phyllosilicate mineral, part of the mica group)
Yellow Jasper
Silicon Dioxide (SiO2) with iron hydroxides (Goethite)
Yellow Beryl (Heliodor)
Beryllium aluminum silicate (Be3Al2Si6O18)
Granite
Phaneritic Igneous Rock (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)
Quartzite
Quartzite (primarily composed of SiO O₂)
Red Quartzite (Ferruginous Quartz)
Quartzite (SiO2 with Fe2O3 inclusions)
Basalt (Vesicular)
Basalt (Extrusive Volcanic Rock)
Fuchsite in Quartz
K(Al,Cr)2(AlSi3O10)(OH)2 + SiO2
Coarse-grained Granite (Quartz and Feldspar dominated)
Granitoid (KAlSi3O8 – NaAlSi3O3 – CaAl2Si2O8 – SiO2)
Porphyritic Rhyolite
Porphyritic Rhyolite (compositionally similar to granite)
Gold Nugget
Native Gold (Au)
Aventurine (specifically Green Aventurine)
Silicon Dioxide (Quartz) with inclusions of Fuchsite; SiO2 + K(Al,Cr)2AlSi3O10(OH)2
River Rock (Quartzite)
Quartzite (SiO2)
Sandstone
Arenite (SiO2 based with quartz, feldspar, or lithic fragments)
Banded Agate
Sedimentary Cryptocrystalline Quartz (SiO2)
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Blue Sapphire
Corundum (Al2O3)
Quartz (possibly milky quartz)
Quartz (Silica; SiO₂)
Shale or Mudstone (Based on appearance)
Shale (fine-grained, laminated fissile sedimentary rock) / Mudstone (fine-grained, non-fissile sedimentary rock)
River Cobble (Quartzite and Iron-stained Quartz)
Quartzite (SiO2 with iron oxide impurities)
Ruby
Corundum (Al2O3 with Chromium traces)
Ferruginous Quartz (Iron-stained Quartzite)
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
Marble
Crystalline Limestone (mostly CaCO3 / Calcium Carbonate)
Ferruginous Sandstone (Ironstone Nodules)
Ferruginous Quartz-Arenite (with Goethite/Hematite cement)
Sandstone (Muddy/Silty Variety)
Arenite with high silt/clay content (clastic sedimentary rock)
Porphyry
Porphyritic Igneous Rock (likely Porphyritic Andesite or Basalt)