Crushed Stone (Gravel/Aggregates)
Crushed rock aggregate (varied composition including Granite, Limestone, and Quartz)
sedimentary and igneous (mixed)
Category
Not A Natural Rock
Browse not a natural rock specimens identified by the Rock Identifier community.
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Amethyst
Amethyst (SiO2 with Iron impurities)
mineral
Petoskey Stone
Hexagonaria percarinata
sedimentary
Sandstone (likely Fossilized Wood or Concrete Simulacrum)
Arenite / Silicified Wood / Anthropogenic Concrete
sedimentary
Aquamarine
Beryl (Be3Al2Si6O18 with iron impurities)
mineral
Emerald in Matrix
Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities
mineral
Chert / Flint Nodular Fragment
Microcrystalline quartz (SiO2)
sedimentary
Asphalt (Bituminous Pavement)
Bituminous mix (Aggregates with Bitumen binder)
sedimentary
Sandstone (Quartz Sandstone)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Hag Stone
Calcareous sedimentary rock (often Chert, Flint, or Limestone)
sedimentary
Granite (River-worn pebble)
Phaneritic plutonic rock (SiO2 + Al2O3)
igneous
Shale
Argillite / Shaly Mudstone
sedimentary
Clear Quartz Crystal (Rock Crystal)
Quartz (Silicon Dioxide, SiO2)
mineral
Sandstone (Quartzose)
Arenite (primarily SiO2)
sedimentary
Sandstone (Quartz Sandstone)
Arenite (primarily SiO2)
sedimentary
Quartzite
Quartzite (SiO2)
metamorphic
Sandstone
Sedimentary Rock (Quartz Sandstone)
sedimentary
Granite
Phaneritic plutonic rock (Quartz, Feldspar, Mica)
igneous
Yellow Quartz (Chalcedony)
Quartz / Chalcedony (Silicon Dioxide, SiO2)
mineral
Sandstone (Feldspathic / Arkose)
Sandstone (SiO2 with variable mineral grains)
sedimentary
Beach Pebble (Gabbro or Basalt Porphyry)
Mafic Igneous Rock (Porphyritic Basalt / Gabbro)
igneous
Green Aventurine
Silicon Dioxide (Quartz) with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)
metamorphic
Ferruginous Sandstone (Ironstone Nodules)
Ferruginous Quartz-Arenite (with Goethite/Hematite cement)
sedimentary
Granite
Phaneritic Plutonic Felsic Rock (SiO2, KAlSi3O8, NaAlSi3O8, CaAl2Si2O8)
igneous
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Granite
Granite (Phaneritic Quartz-Feldspar Plutonic Rock)
igneous
Hag Stone (Holey Rock / Fossiliferous Limestone)
Limestone (CaCO3) with natural erosion / fossil cavities
sedimentary
Granite
Phaneritic intrusive felsic igneous rock
igneous
Granite
Granite (Silica-rich Plutonic Rock)
igneous
Pearl necklace
Pearl (biogenic calcium carbonate, chiefly aragonite; CaCO₃)
gemstone
Man-made Jewelry Charm (Enameled Metal)
Not a natural mineral; composed of base metal alloy (likely zinc or brass) and epoxy resin/enamel.
Synthetic / Manufactured Artifact
Shale
Fissile Mudstone
sedimentary
Clear Quartz Crystal
Silicon Dioxide (SiO2)
mineral
Small dark mineral/rock fragment
Indeterminate; possibly magnetite-bearing basalt or iron-rich slag
mineral
Quartz (Smoky Quartz variant)
Silicon Dioxide (SiO2)
mineral
Pumice (Vesicular Lava)
Pumice
igneous
Chert (Chalcedony/Agate)
Microcrystalline Quartz (SiO2)
sedimentary
Granite (likely Kashmir/ivory-type granite)
Granite; chiefly quartz (SiO₂), feldspar, and mica/amphibole
igneous
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
River Quartzite Siltstone
Quartz-rich Meta-siltstone (SiO2 dominated)
metamorphic