Smoky Quartz (Tumbled)
Silicon Dioxide (SiO2)
mineral
Category
Not A Natural Rock
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Asphalt
Asphalt concrete (engineered material, not a naturally occurring rock/mineral in this form)
Sedimentary
Sandstone (Quartzite-rich)
Clastic Sedimentary Rock (primarily SiO2)
sedimentary
River Pebble Gravel
Hydrothermally modified Clastic Sediment (mainly Quartzite and Chert)
sedimentary
Granite
Granite (composed of Quartz, Feldspar, and Mica/Amphibole)
igneous
Dyed Pink Quartzite (Jadeite Simulant)
Silicon Dioxide (SiO2) with organic dye
metamorphic
Blue Agate Geode (Dyed)
Cryptocrystalline Quartz (SiO2)
mineral
Clear Quartz
Silicon dioxide (SiO2)
mineral
Sandstone (with Iron Staining)
Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 oxides)
sedimentary
Quartzite Pebbles or River Rock
Quartzite / Microcrystalline Quartz (SiO2)
sedimentary
Granite
Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)
igneous
Sandstone Anvil / Nutting Stone
Quartzose Sandstone (Sedimentary Rock)
sedimentary
Granite (Weathered River Rock)
Granite (Phaneritic Igneous Rock)
igneous
Amethyst Geode
Amethyst (Silicon Dioxide, SiO2)
mineral
Sandstone (Ferruginous)
Arenite (with Iron Oxide cement)
sedimentary
River Stone (Basalt or Siltstone)
Basalt (extrusive igneous rock) or fine-grained Siltstone
igneous
Yooperlite (Syenite clast containing fluorescent Sodalite)
Sodalite-bearing Syenite
igneous
Weathered river pebble, likely quartz-rich sandstone or iron-stained quartzite
Provisional identification: quartz-rich sandstone/quartzite; exact composition cannot be confirmed from the image
sedimentary
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
mineral
Smoky Quartz in Matrix
Silicon dioxide (SiO2) within Pegmatite/Gneiss
igneous
Sandstone
Arenite (SiO2 based)
sedimentary
Polished black agate slice
Chalcedony (microcrystalline quartz), SiO₂, with iron/manganese staining
mineral
Sandstone (Weathered)
Arenite (typically SiO2 as quartz grains)
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Emerald in Matrix
Beryl (Be3Al2Si6O18) with trace amounts of Chromium/Vanadium
mineral
Blue Obsidian
Volcanic Glass (SiO2 with inclusions)
igneous
Sandstone (Ferruginous)
Clastic sedimentary rock (primarily SiO2 with Fe2O3 cement)
sedimentary
Sandstone (Stream-rounded Cobble)
Arenite (composed primarily of SiO2, Silica)
sedimentary
Boulder Opal
Hydrated amorphous silica (SiO2·nH2O) in ironstone matrix
mineral
Shale
Shale (Consolidated fine-grained clay/silt)
sedimentary
Shale
Shale (Sedimentary rock composed of mud/clay minerals)
sedimentary
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Basalt (River Pebble)
Extrusive Mafic Igneous Rock
igneous
Turquoise
CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminum)
mineral
Pebble (likely Sandstone or Granitic Pebble)
Clastic Sediment (or specific rock type, e.g., Arenite, Granitoid Pebble)
Rock (likely Sedimentary)
Pumice
Pumice (Volcanic Rock)
igneous
Chert (Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Ferruginous Quartz
Silicon Dioxide (SiO2) with Iron Oxide inclusions
mineral
Yellow Quartz
SiO2 (Crystalline Silicon Dioxide)
mineral
Red Jasper with Quartz
Silicon Dioxide (SiO2) with Hematite impurities
sedimentary
Banded Chert / Chalcedony
Silicon Dioxide (SiO2)
sedimentary
Chert (specifically Flint or Jasper variant)
Microcrystalline quartz (SiO2)
sedimentary