Dyed Agate Slice
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Category
Not A Natural Rock (Man Made Composite)
Browse not a natural rock (man made composite) specimens identified by the Rock Identifier community.
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Chert Conglomerate (or Breccia)
Sedimentary Clastic Rock (variety: Ferruginous Chert Breccia)
sedimentary
Rounded gray pebble
Indeterminate; likely a water-worn silicate or carbonate pebble
sedimentary
Quartz (Herkimer Diamond variant)
Silicon Dioxide (SiO2)
mineral
Quartz crystal pendant
Quartz (silicon dioxide, SiO₂), likely rock crystal or milky quartz
mineral
Banded Agate (Botswana Agate)
Silicon Dioxide (SiO2)
mineral
Likely quartz fragment
Quartz (silicon dioxide, SiO₂), possibly milky quartz or quartz-rich rock
mineral
Slate
Low-grade Metamorphic Rock (composed of quartz, illite, chlorite)
metamorphic
Granite Pebble
Granite (Plutonic Igneous Rock)
igneous
Pink Granite
Phaneritic intrusive felsic igneous rock
igneous
Sandstone Pebble (River Rock)
Sandstone (Quartz-rich sedimentary rock with iron oxide staining)
sedimentary
Sandstone
Clastic Sedimentary Rock
sedimentary
Slate
Slate (Metamorphic rock)
metamorphic
Silicon Carbide (Carborundum)
Silicon Carbide (SiC)
mineral
Rounded gray-brown cobble, likely weathered sandstone or quartzite
Tentatively quartz-rich sandstone (SiO₂-dominated); exact identification requires hardness and acid tests
sedimentary
Granite
Phaneritic Igneous Rock (composed of quartz, alkali feldspar, and plagioclase)
igneous
Granite
Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)
igneous
Water-worn basalt cobble
Basalt; chiefly plagioclase feldspar, pyroxene, and minor olivine/iron oxides
igneous
Pink Dyed Agate
Chalcedony (SiO2) with artificial dyes
mineral
Small rounded pebble
Unidentified lithic clast; likely fine-grained sandstone, mudstone, or basalt
sedimentary
Pink Granite
Phaneritic Felsic Igneous Rock (Granite)
igneous
Hag Stone
Perforated Calcarenite or Chert
sedimentary
Clear Quartz Crystal
Silicon Dioxide (SiO2)
mineral
Quartzite
Quartzite (SiO2)
metamorphic
Fossilized Echinoid / Sea Urchin Internal Mold
Echinoidea internal cast (steinkern)
fossil
Sandstone (Pebble)
Sandstone (SiO2 dominated with minor feldspar/clay)
sedimentary
Green Aventurine
Aventurine Quartz (SiO2 with inclusions)
metamorphic
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Hag Stone (Banded Chert or Limestone with Borehole)
Microcrystalline Quartz (Chert) or Calciferous Siltstone (CaCO3/SiO2)
sedimentary
Amethyst Lace Agate / Banded Amethyst
Silicon Dioxide (SiO2) with Fe3+ impurities
mineral
Sandstone
Sandstone (lithified quartz arenite, arkose, graywacke, etc. depending on composition)
Sedimentary Rock
Lapis Lazuli
Lapis Lazuli (Rock composed primarily of Lazurite (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2, Calcite, and Pyrite)
metamorphic
Siltstone with Fossil Cast
Sedimentary Rock (Siltstone / Fine-grained Sandstone)
sedimentary
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Smoky Quartz
Silicon Dioxide (SiO2) with aluminum impurities and natural irradiation
mineral
Fossiliferous Limestone
Fossiliferous Carbonate Rock (CaCO3)
sedimentary
Pink Granite
Granite (enriched in Potassium Feldspar / Orthoclase)
igneous
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Citrine
SiO2 (Silicon Dioxide)
Mineral
Sandstone (Quartzose Sandstone)
Arenite (primarily SiO2)
sedimentary
Citrine Geode Fragment
Citrine (Silicon Dioxide with Iron Impurities), SiO2
mineral
Yellow Chalcedony (Agate or Citrine Quartz)
Silicon Dioxide (SiO2)
mineral