Tumbled orange agate or carnelian
Microcrystalline quartz (chalcedony), SiO₂; orange coloration commonly from iron oxides
gemstone
Category
Anthropogenic Specimen (Man Made Material)
Browse anthropogenic specimen (man made material) specimens identified by the Rock Identifier community.
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Chert (and Flint)
Silicon Dioxide (SiO2)
sedimentary
Chert (specifically White Chert or Novaculite)
Silicon Dioxide (SiO₂)
sedimentary
Blue-beaded gemstone jewelry, likely lapis lazuli or dyed blue agate
Uncertain from the image; possible lazurite-bearing lapis lazuli (Na₃Ca(Si₃Al₃)O₁₂S) or blue chalcedony (SiO₂)
gemstone
Chert Pebble
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Diorite
Intermediate plutonic igneous rock
igneous
Natural or Cultured Pearl
Calcium Carbonate (Aragonite and Conchiolin), CaCO3
Mineral (Organic)
Jasper
Silicon Dioxide (SiO2)
sedimentary
Aragonite Star Cluster
Aragonite (Calcium Carbonate, CaCO3)
mineral
Brown Chert
Microcrystalline Quartz (SiO2)
sedimentary
Carved quartz skull, likely smoky quartz or gray chalcedony
Silicon dioxide (SiO₂), quartz or microcrystalline quartz
gemstone
Riverstone (Sandstone Pebble)
Arenite (SiO2 with various lithic fragments)
sedimentary
Granite
Granite (Felsic Plutonic Rock)
igneous
Tumbled coral fragment (likely white calcitic coral)
Calcium carbonate, primarily aragonite or calcite (CaCO₃); exact coral genus cannot be determined from the image
fossil
Rough amethyst-bearing quartz specimens
Quartz, SiO₂; purple coloration from trace iron and irradiation
mineral
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Chert (specifically Red Chert or Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Quartz
Silicon Dioxide (SiO₂)
Mineral
Pearls (likely freshwater cultured pearls)
Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin
gemstone
Quartzite Pebble
Quartzite (SiO2)
metamorphic
Coquina / Fossiliferous Limestone
Calcareous bioclastic sedimentary rock (CaCO3)
sedimentary
Quartzite (River Pebble)
Quartzite (Mainly SiO2)
metamorphic
Diamond (Cut Gemstone)
Natural Carbon (C)
gemstone
Quartzite
Quartzite (SiO2)
metamorphic
Iron Slag
Ferrous Slag (complex silicate and oxide byproduct)
industrial byproduct (anthropogenic)
Diorite
Diorite
igneous
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary (fossilized)
Weathered quartz-rich pebble, possibly granitic gneiss
Quartz–feldspar–mica aggregate; likely granitoid or gneiss
metamorphic
Pyrite
Iron Disulfide (FeS2)
mineral
Chert (River Siltstone/Quartzite type)
Microcrystalline Quartz (SiO2)
sedimentary
Chiastolite
Andalusite variety Chiastolite
mineral
Quartz (Iron-Stained / Yellow Quartz)
Silicon Dioxide (SiO2)
mineral
Sandstone (Pebble)
Arenite
sedimentary
Smoky Quartz
Smoky Quartz (Silicon Dioxide, SiO2)
mineral
Fossilized wood fragment
Petrified wood; commonly silicified fossil wood (SiO₂ replacing organic tissue)
fossil
Shale with Trace Fossils
Fissile mudrock (Shale)
sedimentary
Chert (Nodular or Massive Variety)
Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (specifically Black Chert or Flint)
Cryptocrystalline Quartz (SiO2)
sedimentary
Coarse-grained granite or granitic gneiss
Granite; primarily quartz (SiO₂), feldspar, and mica, possibly metamorphosed to gneiss
igneous
Chert / Flint
Silicon Dioxide (SiO2)
sedimentary
Chert (varieties include Flint and Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Iron Slag
Ferrous Slag (Silicate/Oxide mixture)
industrial byproduct (anthropogenic)