Granite Gneiss
Gneiss (High-grade regional metamorphic rock)
Category
Browse organic gemstone (not a rock or mineral) specimens identified by the Rock Identifier community.
Granite Gneiss
Gneiss (High-grade regional metamorphic rock)
Diorite
Diorite (Intermediate intrusive igneous rock)
Blue Apatite
Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)
Limonite Concretion (Ironstone)
Limonite (FeO(OH)·nH2O) / Goethite
Tiger's Eye
Silica (Quartz) pseudomorph after Crocidolite (SiO2)
Granite (Pink/Red)
Phaneritic Plutonic Felsic Rock (major minerals: Quartz, Orthoclase Feldspar, Plagioclase Feldspar)
Orthoclase Feldspar
Orthoclase (KAlSi3O8)
Milky Quartz
Silicon Dioxide (SiO2)
Green Banded Chert (Agate/Jasper)
Silicon Dioxide (SiO2) with trace impurities of Chlorite or Glauconite
Coarse-grained Granite
Phaneritic Granite (contains Quartz, Feldspar, and Mica)
Granite
Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)
Pyrite
Iron Pyrite (FeS2)
Red Sandstone
Arenite (with Iron Oxide cement)
Sandstone with Iron Oxide (Limonite/Hematite)
Ferruginous Sandstone (SiO2 with FeO(OH)·nH2O)
Amethyst Geodes
Silicon Dioxide (Quartz with Iron impurities), SiO2
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Copper-bearing Quartz (likely Chrysocolla or Malachite staining)
Cuprite, Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O) or Malachite staining on Quartz/Host Rock
Quartz / Common Opal
Silicon Dioxide (SiO2)
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
White Quartz (Tumbled)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Basalt with Amygdules
Amygdaloidal Basalt
Cardstock (Paper)
Cellulose (C6H10O5)n
Petrified Wood
Silicified Wood (SiO2 permineralization)
Sandstone (Calcareous Sandstone)
Calcareous Sandstone (primarily SiO2 with CaCO3 cement)
Lake Superior Agate
Cryptocrystalline Quartz (SiO2)
Quartz
Silicon Dioxide (SiO2)
Sodalite
Sodalite (Na8Al6Si6O24Cl2)
Druzy Quartz
Silicon Dioxide (SiO2)
Dyed Agate
Chalcedony (Silicon Dioxide, SiO2)
Sandstone (Ferruginous)
Arenite (SiO2 with iron oxide impurities)
Sandstone (with potential trace fossils)
Clastic sedimentary rock (primarily SiO2)
Sandstone (likely Greywacke variant)
Arenite
Sandstone
Arenite (SiO2 based)
Sandstone (Quartzose)
Arenite (composed mainly of SiO2)
Sandstone
Arenite (SiO2 based)
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2)
Sandstone
Arenite (primarily SiO2)
Sedimentary Sandstone (Sandstone Slab)
Arenite (SiO2 with Fe2O3 staining)
Sandstone (Yellow/Tan Sandstone)
Arenite (primarily Quartz, SiO2)
Sandstone (Quartzose Sandstone)
Arenite (composed primarily of SiO2)
Sandstone (Ferruginous)
Arenite with Iron Oxide matrix