Pink Granite
Phaneritic Felsic Igneous Rock (composed primarily of Quartz and Potassium Feldspar)
igneous
Category
Industrial Byproduct (Anthropogenic Rock)
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Basalt
Basalt (Mafic Extrusive)
igneous
Pumice and Scoria
Vesicular Volcanic Rock (Pumice: Silicic / Scoria: Mafic)
igneous
Basalt
Basalt (composition predominately Plagioclase feldspar and Pyroxene)
igneous
Obsidian (black volcanic glass)
Obsidian; primarily amorphous SiO₂-rich rhyolitic glass
igneous
Druzy Quartz on Chert/Siltstone
Silicon Dioxide (SiO2) on Microcrystalline Silica/Siltstone matrix
sedimentary
Fossilized Bone
Permineralized Vertebrate Bone
fossil
Basalt (Greenstone/Water-worn Pebble)
Basalt (containing Chlorite/Epidote)
igneous
Red Sandstone
Sedimentary Arenite / Quartzose Sandstone
sedimentary
Desert Varnish on Sandstone
Ferromanganese coating on Quartz Arenite
sedimentary
Basalt
Mafic extrusive igneous rock
igneous
Herkimer Diamond
Quartz (Silica - SiO2)
mineral
Painted Sandstone
Sandstone (clastic sedimentary rock) with acrylic/artistic coating
sedimentary
Quartzite River Pebbles
Quartzite (primarily SiO2)
Metamorphic
Cultured Marble (Synthetic)
Polymer-matrix composite (typically calcium carbonate in polyester resin)
Synthetic / Composite Material
Vuggy Quartz on Matrix
Crystalline Silicon Dioxide (SiO2)
mineral
Smooth river pebble
Indeterminate lithology; likely fine-grained quartz-rich sandstone, siltstone, or weathered chert
sedimentary
Opalite
Synthetic Opalite (Man-made glass)
mineral
Aura Quartz (Pink/Rose Aura Quartz)
Silicon Dioxide (SiO2) bonded with Platinum and/or Silver
mineral
Quartz (Engineered Stone Countertop)
Silicon Dioxide (SiO2) within a resin matrix
igneous
River Rocks (Black)
Various lithologies (e.g., basalt, chert, obsidian for black varieties), mechanically rounded clasts
Sedimentary
Sandstone (with potentially high Feldspar/Arkose content)
Clastic sedimentary rock (SiO2 dominated)
sedimentary
Granite
Granite
Igneous
Chert
Chert (microcrystalline quartz, SiO2)
Sedimentary
Weathered garnet-bearing gneiss
Quartz–feldspar–mica gneiss with almandine garnet, chiefly Fe₃Al₂(SiO₄)₃
metamorphic
Water and Silt (Sedimentary Environment)
Suspended Sediment / H2O (dihydrogen monoxide)
sedimentary
Basalt Pebble
Extrusive Igneous Rock (Mafic)
igneous
Granite
Intrusive Igneous Rock
igneous
Shale with Quartz Veins
Fissile Sedimentary Rock (SiO2)
sedimentary
Basalt
Extrusive mafic igneous rock
igneous
Breciated Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Ironstone (Limonitic Sandstone)
Ferruginous Sandstone (rich in Limonite: FeO(OH)·nH2O)
sedimentary
Chert (containing Flint nodules)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Hag Stone (Adder Stone / Geode-bearing Pebble)
Sedimentary Rock with Cavity (often Quartzite, Limestone, or Sandstone)
sedimentary
Diamond
Diamond (pure carbon, C)
gemstone
Sandstone (with Iron Staining)
Arenite (primarily SiO2 with Fe2O3/FeO(OH) oxides)
sedimentary
Red synthetic corundum (ruby-colored lab-grown sapphire)
Corundum, aluminum oxide (Al₂O₃), likely synthetic and chromium-colored
gemstone
Tumbled brown stone, likely smoky quartz or brown jasper
Probable smoky quartz (SiO₂) or iron-rich jasper (microcrystalline SiO₂); image alone is insufficient for certainty
mineral
Polished agate (likely fire agate or carnelian-bearing agate)
Microcrystalline quartz, SiO₂; chalcedony with iron-oxide inclusions
gemstone
Green aventurine quartz sphere
Quartz, SiO₂, with fuchsite or other green mica inclusions
mineral
Pegmatite (Quartz and Feldspar with Dark Minerals)
Igneous Pegmatite
igneous
Agate
Silicon Dioxide (Chalcedony), SiO2
sedimentary