Citrine
Silicon Dioxide (SiO2)
mineral
Category
Mineralogical
Browse mineralogical specimens identified by the Rock Identifier community.
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Manganese Dendrite on Siltstone
Manganese Oxide (pyrolusite or psilomelane) Dendrites
mineral/sedimentary
Pyrite Sun (Pyrite Dollar)
Iron Disulfide (FeS2)
mineral
Geode with Quartz/Chalcedony
Silicon Dioxide (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Dendritic Quartz
Silicon Dioxide (SiO2) with Manganese Oxide inclusions
mineral
Weathered greenish rock fragment
Indeterminate; possibly epidote- or chlorite-bearing altered silicate rock
mineral
Tumbled green aventurine (probable)
Quartz, SiO₂, with fuchsite mica inclusions
mineral
Tumbled kambaba jasper (likely)
Kambaba jasper, a silica-rich microcrystalline quartz aggregate, commonly containing fossilized cyanobacterial structures and dark green amphibole/pyroxene minerals
sedimentary
Fossilized oyster shell in limestone
Bivalvia fossil; chiefly calcite (CaCO₃)
fossil
Graphite Schist
C (Carbonaceous Schist)
metamorphic
Dalmatian jasper
Orbicular microcrystalline quartz rock, commonly rhyolitic or volcanic-feldspar matrix with black arfvedsonite/alkali-amphibole inclusions
igneous
Mixed River Pebbles (Jasper, Hematite, and Quartzites)
Silicon dioxide (Jasper/Quartz) and Iron oxide (Hematite)
sedimentary
Labradorite
(Ca, Na)(Al, Si)4O8 (Calcium Sodium Aluminum Silicate)
mineral
Sand Grain (Quartz)
Silicon Dioxide (SiO2)
sedimentary
Iron Slag
Iron smelting byproduct (Glassy/vesicular silicate)
anthropogenic / industrial byproduct
Hag Stone
Sandstone or Limestone with Solution Holes (Bioturbation/Erosion)
sedimentary
Rhyolite
Extrusive Felsic Igneous Rock
igneous
Granite (Alkali-feldspar Granite)
Felsic Plutonic Rock (Primary minerals: Quartz SiO2, Orthoclase KAlSi3O8, Plagioclase (Na,Ca)AlSi3O8)
igneous
Basalt with Plagioclase Phenocrysts
Porphyritic Basalt
igneous
Pink Granite
Granite (Phaneritic intrusive igneous rock)
igneous
Quartzite
Quartzite (primarily SiO2)
metamorphic
Granite (with Orthoclase and Quartz)
Phaneritic Felsic Igneous Rock (KAlSi3O8 + SiO2)
igneous
River Pebbles (Stream-rounded rocks)
Fluvial Detritus (varied mineralogy)
Mixed (predominantly sedimentary and igneous)
Greenstone / Glauconitic Siltstone
Metabasalt or Glauconite-rich Sedimentary Rock
metamorphic or sedimentary
Tiger's Eye (with Hematite/Jasper)
SiO2 (Silicon Dioxide) with Fe2O3 (Hematite)
mineralogical
Optical Calcite
Calcium Carbonate (CaCO3)
mineral
Tumbled dark green stone, likely serpentine
Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄)
metamorphic
Small brown-gray mineral fragment
Indeterminate; possibly weathered quartz-, feldspar-, or iron-oxide-bearing rock
mineral
Tumbled orange chalcedony and a gray stone disk
Chalcedony (microcrystalline quartz, SiO₂); disk likely fine-grained sandstone or slate
mineral
Limestone or Sandstone Cobble
Sedimentary rock (Calcium carbonate or Quartz based)
sedimentary
Granodiorite
Granodiorite (containing Plagioclase, Quartz, and Biotite)
igneous
Granitic Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Granite
Phaneritic Plutonic Felsic Rock
igneous
Granite (Fine-grained)
Phaneritic Felsic Igneous Rock
igneous
Granite
Granite (Felsic Plutonic Rock)
igneous
Granite
Phaneritic Plutonic Igneous Rock (Granite)
igneous
Granite
Phaneritic Igneous Rock (composed of quartz, alkali feldspar, and plagioclase)
igneous
Granite
Felsic Intrusive Igneous Rock
igneous
Weathered iron-rich volcanic rock
Likely altered basalt or andesite with iron-oxide staining
igneous
Sandstone Concretion
Ferruginous Sandstone Concretion (Primarily SiO2 with Iron Oxide cement)
sedimentary
Diorite
Diorite (an intermediate intrusive igneous rock)
igneous