Sandstone
Arenite (SiO2 dominant)
sedimentary
Category
Mineral Based Composite
Browse mineral based composite specimens identified by the Rock Identifier community.
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Polished chalcedony (likely sagenite or included agate)
Microcrystalline quartz, SiO₂, with iron-oxide and possibly rutile/goethite inclusions
gemstone
Blue-green amphibole-bearing rock (possibly actinolite schist)
Likely actinolite-rich rock; actinolite, Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂
metamorphic
Otodus Shark Tooth
Otodus obliquus
fossil
Sandstone (Siltstone or Fine-grained)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Carved turquoise arrowhead/pendant
Turquoise, hydrated copper aluminum phosphate — CuAl₆(PO₄)₄(OH)₈·4H₂O
gemstone
River Pebble
Quartzite / Weathered Sedimentary Rock
sedimentary
Small polished jasper or agate pebble
Likely microcrystalline quartz (SiO₂); exact variety cannot be determined from the photo
mineral
Polished malachite
Malachite (Cu₂CO₃(OH)₂), a hydrated copper carbonate hydroxide
mineral
Polished malachite slab
Malachite, Cu₂CO₃(OH)₂; likely polished and possibly resin-stabilized
mineral
Fossilized Shark Tooth
Bioapatite (Calcium Hydroxyapatite) replacement
mineral
Moss Agate
Silicon Dioxide with inclusions (SiO2)
mineral
Fossilized Crinoid Stem Cross-Section
Crinoidea
fossil
Sandstone
Arenite (Sedimentary rock composed of sand-sized grains)
sedimentary
Brown Banded Calcite
Calcium Carbonate (CaCO3)
mineral
Polished yellow jasper cabochon
Jasper, microcrystalline quartz (SiO₂) with iron-oxide and clay inclusions
metamorphic
Chert with Chalcedony/Quartz Vug
Cryptocrystalline Silica (SiO2)
sedimentary
Granite Thin Section
Granitic rock (Phaneritic texture)
igneous
Sandstone
Arenite (primarily Quartz-based)
sedimentary
Sandstone
Arenite (SiO2 based typically)
sedimentary
Sandstone
Arenite (SiO2 based typically)
sedimentary
Sandstone (Quartz Sandstone / Iron-stained Sandstone)
Sandstone (SiO2 with iron oxide impurities)
sedimentary
Small tumbled blue-green stone, possibly chrysocolla or turquoise
Indeterminate copper-bearing mineral; possible chrysocolla (Cu₂H₂Si₂O₅(OH)₄·nH₂O) or turquoise (CuAl₆(PO₄)₄(OH)₈·4H₂O)
mineral
Fossil / Permineralized Bone
Tyrannosaurus rex fossil (Hydroxylapatite replaced by various minerals)
sedimentary
Gold Mineral
Native Gold (Au)
mineral
Opalite crescent pendant
Opalite (man-made opalescent glass; not a natural mineral)
gemstone
Dendritic sandstone
Sandstone with Manganese Oxide dendrites
sedimentary
Sandstone
Arenite (SiO2 based with various mineral cements)
sedimentary
Sandstone
Arenite (SiO2 based with various mineral cements)
sedimentary
Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite
sedimentary
Sandstone (likely Calcareous or Quartz-rich)
Arenite (SiO2 based typically)
sedimentary
Banded Onyx (Mexican Onyx / Travertine)
Calcite (CaCO3) - Banded Travertine
sedimentary
Sandstone Pebble
Arenite (SiO2 with minor mineral cements)
sedimentary
Sandstone (Ferruginous)
Arenite (SiO2 based with Fe2O3 banding)
sedimentary
Sandstone (with potential trace fossils)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Engineerged Quartz (Quartz Composite)
SiO2 (Silicon Dioxide) in a polymer resin matrix
mineral
Opalite glass sphere (likely synthetic imitation)
Man-made opalescent glass; not natural opal
mineral
Rose Quartz
Silicon dioxide (SiO2) with traces of titanium, iron, or manganese
mineral
Unakite
Unakite Epidosite (composite of Epidote, Orthoclase, and Quartz)
metamorphic
Granite
Granite (Phaneritic Igneous Rock)
igneous
Likely blue-green glassy slag or a weathered mineral fragment
Unidentified; the image does not show diagnostic features sufficient for a mineral identification
mineral