Anthracite Coal
Anthracite (Carbon-rich Sedimentary-to-Metamorphic Rock)
Category
Browse industrial byproduct (often confused with igneous rocks or meteorites) specimens identified by the Rock Identifier community.
Anthracite Coal
Anthracite (Carbon-rich Sedimentary-to-Metamorphic Rock)
Druzzy Quartz on Matrix
Silicon Dioxide (SiO2)
Chalcedony (Common Opal or Agate variant)
Silicon Dioxide (SiO₂)
N/A - Man-made object (Jewelry Chain)
Antiqued or Oxidized Metal Chain (often Steel or Brass)
Opaline Glass (Opalite)
Synthetic Silicon Dioxide Glass
Sandstone (Quartzose Sandstone)
Arenite (primarily SiO2)
Red Sandstone
Arenite (with Iron Oxide / Hematite cementation)
Chert (specifically Flint or Gray Chalcedony)
Microcrystalline Quartz (SiO2)
Jasper pebble
Jasper (Silicon Dioxide, SiO2)
Limestone (specifically Crushed Limestone/Calcictic)
Calcium Carbonate (CaCO3)
Asphalt / Bituminous Aggregate
Bituminous mixture (Hydrocarbon-based sediment)
Red Chert
Microcrystalline Quartz (SiO2)
Ferruginous Sandstone (Gerrit)
Arenite with Iron Oxide cementation
Rough Diamond
Native Carbon (C)
Industrial Diamond (Bort or Boart)
Diamond (pure Carbon, C)
Silver (Native or Alloyed)
Ag (Argentum)
Quartz Geode
Silicon Dioxide (SiO2)
Basalt (Water-worn pebble)
Mafic Igneous Rock (primarily Plagioclase feldspar and Pyroxene)
Quartzite
Quartzite (primarily SiO2)
Pink Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Chert (often called Flint)
Chert (Silicon Dioxide, SiO2)
Green Calcite
Calcium Carbonate (CaCO3)
Gold and Diamond
Native Gold (Au) and Diamond (C)
Ferruginous Quartz
Iron-stained Quartz (Silicon Dioxide + Fe2O3 / FeO(OH))
Agate
Silicon dioxide (SiO2)
Bouncy Ball (Synthetic Rubber Polymer)
Polybutadiene / Ethylene Vinyl Acetate (EVA)
Anthracite Coal
Anthracite (Metamorphosed Coal)
Limonite and Goethite
Limonite (hydrated iron(III) oxide-hydroxide) and Goethite (α-FeO(OH))
Biotite Schist (with Garnet and Pyrite)
K(Mg,Fe)3AlSi3O10(OH,F)2 (Biotite focus)
Banded Chert
Microcrystalline Quartz (SiO2)
Orange Calcite
Calcite (Calcium Carbonate, CaCO3)
Sandstone (Pebble)
Arenite (primarily SiO2)
Quartz / Common Opal Transition
Silicon Dioxide (SiO2)
Specular Hematite
Hematite (Iron Oxide, Fe2O3)
Chert (Flint Nobule)
Silicon Dioxide (SiO2)
Green Aventurine (Quartz)
SiO2 (Silicon Dioxide with Fuchsite inclusions)
Sandstone (Ferruginous)
Arenite (composed primarily of SiO2 with Fe2O3 cement)
Granite
Granite
Banded Agate (Gray Agate)
Silicon Dioxide (SiO2) - Chalcedony
Orange Calcite
Calcite (Calcium Carbonate - CaCO3)
Banded Chert (Flint/Jasper variety)
Microcrystalline Quartz (SiO2)
Granite
Granite (phaneritic intrusive igneous rock consisting mainly of quartz, alkali feldspar, and plagioclase)