Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
Mineral
Category
Man Made Material, Not A Natural Rock Or Mineral Specimen
Browse man made material, not a natural rock or mineral specimen specimens identified by the Rock Identifier community.
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River Cobble (Basaltic/Andesitic)
Mafic to Intermediate Volcanic Rock
igneous
Sandstone
Arenite (primarily Quartz, SiO2)
sedimentary
Milky quartz-bearing rock, possibly quartzite
Quartz (SiO₂), likely in a quartzite or quartz-rich metamorphic matrix
metamorphic
Turquoise cabochon
Turquoise; hydrated copper–aluminum phosphate, approximately CuAl6(PO4)4(OH)8·4H2O (composition varies)
gemstone
Cullet Glass (Industrial Slag Glass)
Amorphous Silica (SiO2) with metallic oxide impurities
Man-made byproduct (often mistaken for Obsidian or Emerald)
Granite Pebble
Phaneritic Felsic Igneous Rock (Granite)
igneous
Sandstone (Quartzose)
Arenite (SiO2 based)
sedimentary
Tumbled carnelian agate with dark mineral inclusions
Carnelian, an orange variety of microcrystalline quartz (chalcedony), SiO₂; dark inclusions are likely iron oxides/hydroxides, possibly hematite, goethite, or a basaltic/matrix fragment
gemstone
Sandstone
Arenite (SiO2 based)
sedimentary
Sandstone (likely Siltstone or fine-grained Sandstone)
Sedimentary Rock (Clastic)
sedimentary
Yellow Quartz (Citrine or Iron-Stained Quartz)
Silicon Dioxide (SiO2)
mineral
Sandstone (lithic wake or graywacke)
Clastic sedimentary rock (primarily quartz and lithic fragments)
sedimentary
Likely tumbled quartz-rich pebble
Quartz (SiO₂), possibly a weathered quartzite or chalcedony pebble
mineral
Sandstone
Sandstone (SiO2 dominant)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Diamond
Carbon (C)
mineral
Rock Fragment with Calcite/Quartz Vein
Polymictic Rock Fragment (SiO2 / CaCO3)
igneous
Quartzite
Metamorphic quartz rock (SiO2)
metamorphic
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone (Quartzite-rich Pebble)
Arenite (primarily SiO2)
sedimentary
Purple Dyed Dalmatian Stone
Dyed Peralkaline Trachyte
igneous
Sandstone (with vugs)
Arenite / Sedimentary Sandstone
sedimentary
Chalk
Carbonate rock (mainly CaCO3)
sedimentary
Ocean Jasper or Orbicular Jasper
SiO2
mineral
Belemnoit (Fossil)
Belemnoidea (Order), Rostrum / Guard
sedimentary
Titanium Quartz (Aura Quartz)
Silicon Dioxide (SiO2) treated with Titanium
mineral
Ironstone / Hematite Concretion
Iron oxide / Fe2O3
sedimentary
Quartz (Citrine or Iron-stained Quartz)
Silicon Dioxide (SiO2)
mineral
Slate
Slate (foliated metamorphic rock)
metamorphic
Sandstone
Arenite (Silicon Dioxide with various mineral cements)
sedimentary
Likely weathered mica schist fragment
Mica schist, chiefly muscovite/biotite mica with quartz and feldspar
metamorphic
Blue Goldstone
Aventurine Glass
Man-made glass (often grouped with minerals in lapidary)
Chert (Holey Stone)
Microcrystalline Quartz (SiO2)
sedimentary
Tufa Rock and Tumbled Gemstones
Calcareous Tufa (Calcium Carbonate, CaCO3)
sedimentary
Tumbled chalcedony or quartz-rich stone
Microcrystalline quartz, SiO₂; possibly pale chert or chalcedony
mineral
Granite
Phaneritic intrusive igneous rock
igneous
Quartz Vein in Hematitic Siltstone
Hydrothermal Quartz (SiO2) in Ferriferous Matrix
metamorphic
Raw Diamond (Rough Uncut)
Diamond (C - pure carbon)
mineral
Sandstone (Quartz-rich)
Sandstone (SiO2 dominated)
sedimentary
Sandstone (Ferruginous)
Arenite with Iron Oxide matrix
sedimentary
Chert (Flint / Jasper)
Silicon Dioxide (SiO2)
sedimentary