Fulgurite
Lechatelierite (Silica glass), typically SiO2
mineraloid
Category
Not A Geological Specimen
Browse not a geological specimen specimens identified by the Rock Identifier community.
Limonite/Goethite on Shale
Hydrous ferric oxides (FeO(OH)·nH2O) often associated with argillaceous rock
sedimentary
Graphic Granite
Graphic Granite (Granitic Pegmatite), typically KAlSi3O8 (Feldspar) + SiO2 (Quartz)
igneous
Ironstone Concretion / Limonite Node
Goethite and Limonite (FeO(OH) nH2O)
sedimentary
Sandstone (Ferruginous)
Arenite (composed primarily of SiO2 with Fe2O3 cement)
sedimentary
Chert (with possible fossils)
Microcrystalline quartz (SiO2)
sedimentary
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz on Matrix
Silicon Dioxide (SiO2)
mineral
Red Jasper (Amygdaloidal Basalt with Agate)
Silicon dioxide (SiO2) in Basalt host
igneous
Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3 with Carotenoid pigments)
Mineraloid (Organic Gemstone)
Quartz with Mica inclusions (likely Schist or Gneiss host)
Silicon Dioxide (SiO2) with Phyllosilicates (KAl2(AlSi3O10)(OH)2)
metamorphic
Nickel coin (U.S. currency)
Cupronickel (75% Copper, 25% Nickel alloy)
man-made alloy (metallic)
Pyrite
Iron Sulfide (FeS2)
mineral
Chalcedony (River Stone)
Microcrystalline Quartz (SiO2)
mineral
Sandstone
Arenite (SiO2 principal component)
sedimentary
Milky Quartz with Chlorite/Moss Infusions
Silicon Dioxide (SiO2)
mineral
Snowflake Obsidian
Vitreous Volcanic Rock (Amorphous Silicate), SiO2
igneous
Smoky Quartz (with Iron Oxidation)
Silicon Dioxide (SiO2)
mineral
Silver (Jewelry Specimen)
Native Silver (Chemical Formula: Ag)
mineral
Granitic Pegmatite with Tourmaline and Sphalerite
Pegmatite containing Schorl (NaFe3Al6(BO3)3Si6O18(OH)4) and Sphalerite ((Zn,Fe)S)
igneous
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
mineral
Milky Quartz (Water-worn Pebble)
Quartz (Silicon Dioxide) - SiO2
mineral
White Quartz (Carved or Tumbled)
Silicon Dioxide (SiO2)
mineral
Synthetic Resin (Artificial Specimen)
Polyurethane or Polyester Resin
mineraloid (man-made)
Quartz (Milky/Smoky variety)
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon dioxide (SiO2)
mineral
Pyrite in Quartz (Drill Core)
Silicon Dioxide (SiO2) with Iron Sulfide (FeS2) inclusions
igneous/metamorphic (hydrothermal)
Petrified Wood
Silicified Wood (SiO2)
mineral
Asphalt (Bituminous Pavement Bit)
Bitumen-bound aggregate (Petrochemical-bound composite)
sedimentary (anthropogenic/technogenic)
Quartz / River Cobble
Silicon Dioxide (SiO2)
mineral
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Fossil Coral
Scleractinia (fossilized calcium carbonate)
sedimentary
Pink Granite
Phaneritic Plutonic Igneous Rock (high K-feldspar)
igneous
Clear Quartz
SiO2 (Silicon Dioxide)
mineral
Rose Quartz (Aura Quartz)
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
mineral
Cobaltian Calcite (Cobaltoan Calcite)
Cobalt-bearing Calcite (Ca,Co)CO3
mineral
Goniatite Fossil
Goniatitida (Order), fossilized in limestone/calcite (CaCO3)
sedimentary
Biotite Schist
Biotite-rich Schist (K(Mg,Fe)3AlSi3O10(F,OH)2)
metamorphic
Fulgurite
Fulgurite (Lechatelierite), amorphous SiO2
metamorphic
Chert (or Flint)
Chert (Sedimentary Cryptocrystalline Sio2)
sedimentary
Granite
Granite (Phaneritic Igneous Rock)
igneous
Erythrite
Erythrite (Cobalt Bloom) - Co3(AsO4)2·8H2O
mineral