Quartz
Silicon Dioxide (SiO2)
mineral
Category
Igneous, Metamorphic, And Sedimentary (Mixed Assemblage)
Browse igneous, metamorphic, and sedimentary (mixed assemblage) specimens identified by the Rock Identifier community.
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Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Raw Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Magnetite / Ironstone Pebble
Magnetite (Fe3O4)
mineral
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Zoisite with Rubellite (Ruby in Zoisite)
Zoisite with inclusions of Hornblende (Anyolite)
metamorphic
Zoisite with Ruby
Anyolite (Calcium aluminum hydroxy silicate with Corundum) Ca2Al3(SiO4)3(OH)
metamorphic
Quartz and Unakite
SiO2 (Quartz) / Epidote, Pink Orthoclase, Quartz (Unakite)
mineral/igneous
Quartz
Silicon Dioxide (SiO2)
mineral
Rounded gray stone, likely weathered chert or quartz-rich river pebble
Chert (microcrystalline SiO₂), tentative
sedimentary
Red porphyritic volcanic rock, likely rhyolite or andesite
Porphyritic rhyolite–andesite; predominantly quartz/feldspar with iron-oxide staining
igneous
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz pebble
Silicon dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz Boulder
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Mixed tumbled gemstone chips
Polychrome jasper, quartz/chalcedony, feldspar, and other silicate fragments (exact identification requires testing)
mineral
Dark mafic rock, possibly basalt or meteorite-like specimen
Likely basalt (plagioclase–pyroxene assemblage); meteorite identification cannot be confirmed visually
igneous
Dark granitic gneiss or fine-grained granite
Biotite granite, possibly weakly foliated gneiss; quartz–feldspar–biotite assemblage
igneous
Quartz
SiO2
mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Quartz or possibly Jasper/Chert. Looks like a tumbled or water-worn stone.
SiO2 (Silicon Dioxide)
Mineral or Sedimentary (if chert)
Limonite (Ironstone Concretion)
Limonite (Hydrous Ferric Oxides mixed with Goethite)
sedimentary
Common River Pebbles and Stones
Mixed natural stream gravel / siliciclastic pebbles
sedimentary
River Rock
Mixed composition, often quartzite, sandstone, or basalt
sedimentary
Siltstone
Siltstone (composed of mixed silicate minerals and clay)
sedimentary
River Rocks and Pebbles
Mixed Silica-rich Sediments (SiO2 based)
sedimentary