Banded Gneiss
Gneiss (Metamorphic Rock)
Category
Browse organic gemstone (not a rock or mineral) specimens identified by the Rock Identifier community.
Banded Gneiss
Gneiss (Metamorphic Rock)
Olivine (Peridot)
Magnesium Iron Silicate (Mg, Fe)2SiO4
Sandstone (Picture Sandstone)
Arenite (primarily SiO2)
Bauxite / Iron-rich Laterite
Laterite (principally Al(OH)3, Fe2O3, and SiO2)
Opalite (Man-made Glass)
Fused glass (typically made of dolomite and metal opacifiers)
Jasper (Mookaite variety likely)
Silicon Dioxide (SiO2) with iron oxide inclusions
River Stone / Pebble
Clastic Sediment (composed largely of Quartz, Feldspar, and various rock fragments)
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Lapis Lazuli
Na6Ca2(Al6Si6O24)(SO4,S,Cl,OH)2 (Lazurite-dominated rock)
Quartz Veined Rock (Likely Graywacke or Quartzite)
Silicon Dioxide (SiO2) veins in Metasedimentary matrix
Sandstone (specifically Banded Sandstone)
Clastic sedimentary rock (primarily SiO2)
Basalt Porphyry
Porphyritic Basalt
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic Extrusive volcanic rock)
Granite
Phaneritic Plutonic Igneous Rock (primarily composed of quartz, alkali feldspar, and plagioclase)
Sandstone (with Limonite staining)
Arenite (primarily SiO2 with FeO(OH)·nH2O)
Quartz
Silicon Dioxide (SiO₂)
Schist
Mica Schist (primarily consisting of muscovite KAl2(AlSi3O10)(OH)2 or biotite K(Mg,Fe)3(AlSi3O10)(OH)2)
Chert (Jasper variety)
Silicon Dioxide (SiO2)
Sandstone
Arenite (SiO2 primarily)
Granite
Phaneritic Plutonic Felsic Rock
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Petrified Wood
Silicified wood (SiO2 - Silicon Dioxide)
Petrified Wood (Silicified Wood)
Silicified Paleoflora (mainly Quartz, SiO2)
Petrified Wood
Silicified wood (Quartz variant, SiO2)
Petrified Wood
Silicified Wood (SiO2)
Clear Quartz (Tumbled)
Silicon Dioxide (SiO2)
Glauconite (Glauconitic Sandstone)
Glauconite [(K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2]
Sandstone (with possibly iron oxides and other minerals)
Sandstone
Turquoise (Dyed Howlite or Magnesite imitation)
Hydrated phosphate of copper and aluminum / CuAl6(PO4)4(OH)8·4H2O
Peridot (Olivine)
Olivine ((Mg, Fe)2SiO4)
Opalite
Synthetic Opalised Glass
Peridot (Gem-quality Olivine)
Magnesium Iron Silicate ((Mg, Fe)2SiO4)
Glauconitic Sandstone
Glauconitic Quartz-Wacke / Sandstone (Fe(II),Fe(III),Al,Mg)2-3(Si,Al)4O10(OH)2
Fossiliferous Chert with Brachiopod Impression
Chert (SiO2) containing Brachiopoda fossil remains
Sandstone
Sandstone (various mineral compositions)
Sandstone or Limestone
Arenite or Calcareous Sedimentary Rock
Chert (Arrowhead Fragment)
Microcrystalline Quartz (SiO2)
Amethyst
Amethyst (Silicon Dioxide - SiO2)
Pebble (Likely Basalt or Siltstone)
Clastic sedimentary rock or mafic volcanic rock
Quartzite River Rock
Quartzite (primarily SiO2)
Shale
Laminated Mudstone
Chert (Flint nodule)
Silicon dioxide (SiO2)