Chert (variations include Flint or Jasper)
Chert (Silicon Dioxide, SiO2)
sedimentary
Category
Mineral Specimen
Browse mineral specimen specimens identified by the Rock Identifier community.
Chert (Chert Nodule)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Tiger's Eye (likely Hawk's Eye variant)
Pseudomorph of Quartz after Crocidolite (SiO2)
metamorphic
Quartzite River Rock
Quartzite (SiO2)
metamorphic
Granite Pebble
Granite (composed mainly of Quartz, Feldspar, and Mica)
igneous
Quartzite
Metamorphic Quartz (SiO2)
metamorphic
Quartzite
Quartzite (SiO2)
metamorphic
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Quartzite
Quartzite (SiO2)
metamorphic
Obsidian Arrowhead
Volcanic Glass (70% or more SiO2)
Igneous
Quartzite Pebble
Metamorphosed Sandstone (SiO2)
metamorphic
Red Jasper
Jasper (Silicon Dioxide with Iron Oxide inclusions, SiO2)
sedimentary
Granite Cobble
Granite (Phaneritic Igneous Rock)
igneous
Hand-Drawn Trading Card (Amateur Artwork)
Cellulose-based substrate with wax/graphite/ink deposit (n/a for minerals)
Organic/Synthetic Composite (Paper and Pigment)
Basalt
Basalt (Mafic volcanic rock)
igneous
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Basalt (River Stone)
Basalt
igneous
Basalt with Iron Oxidation
Amygdaloidal Basalt (silicate rock primarily plagioclase, pyroxene, and olivine)
igneous
Chert (Gravel specimen)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Unknown Rock Specimen
igneous
River Stone / Pebble
Clastic Sediment (composed largely of Quartz, Feldspar, and various rock fragments)
Mineral, Sediment
Almandine Garnet
Almandine (Fe3Al2(SiO4)3)
mineral
Fursuit (Synthetic Fur Specimen)
Canis anthropomorphus syntheticus
Anthropomorphic Textile Construct
Limestone (specifically Travertine or Tufa)
Calcium Carbonate (CaCO3)
sedimentary
River Rock (likely Quartzite or Quartz-rich Siltstone)
Quartzite (SiO2)
metamorphic
Goethite (likely as part of Limonite/Ironstone)
Goethite (α-FeOOH)
Mineral
Concretion or Geode (unbroken)
Varied (depending on mineral composition and cementing agent). For quartz-lined geodes, the scientific name of the dominant mineral would be Quartz (SiO2). For calcite-lined geodes, Calcite (CaCO3). Concretions are often composed of cryptocrystalline quartz (chert), calcite, or iron oxides.
Sedimentary rock (specifically a concretion or possibly a geode)
Green Aventurine (Green Quartz)
Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2(AlSi3O10)(OH)2)
Mineral/Metamorphic rock
Gold Nugget
Native Gold (Au)
mineral
Epidote (or Epidote-rich rock)
Epidote. Mineral formula: Ca2(Al,Fe)3(SiO4)3(OH).
Mineral, often found in metamorphic rocks but also in sedimentary and igneous rocks
Feldspar Rich Granite with Limonite Staining
K-Feldspar Granite (KAlSi3O8)
igneous
Pyrite (or Fool's Gold)
Pyrite (FeS₂)
Mineral
Quartz (Druzy) in host rock
SiO₂ (Silicon Dioxide) as Quartz, with unspecified host rock components (likely silicates and iron oxides)
Mineral
Red Jasper (Tumbled)
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Gold Nugget
Native Gold (Au)
mineral
Pegmatite with Muscovite
Granitic Pegmatite (KAl2(AlSi3O10)(OH)2)
igneous
Coal (Anthracite)
Anthracite (Carbon-based organic sedimentary/metamorphic rock)
metamorphic
Muscovite Schist with Quartz
KAl2(AlSi3O10)(OH)2 in Schistose matrix
metamorphic
Gneiss (Cobble)
Gneiss
metamorphic
Dark-colored Igneous Rock (likely Basalt or Diabase)
Basalt (extrusive igneous) or Diabase (intrusive igneous)
Igneous Rock
Dyed Agate (Tumbled)
Silicon Dioxide (SiO2) - stained microcrystalline quartz
sedimentary
Quartzite
Quartzite (primarily SiO2)
metamorphic