Quartz Geode (Smoky Quartz)
Silicon Dioxide (SiO2)
mineral
Category
Synthetic (Not A Natural Rock)
Browse synthetic (not a natural rock) specimens identified by the Rock Identifier community.
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Turquoise
Hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O
mineral
Agate (specifically Botswana or Banded Agate variety)
Chalcedony (Silicon Dioxide, SiO2)
mineral
Pink Granite
Phaneritic Felsic Igneous Rock
igneous
Smooth gray river pebble
Likely fine-grained sandstone or siltstone; exact identification requires a fresh surface and tests
sedimentary
Granite
Intrusive Felsic Igneous Rock (primarily Quartz and Feldspar)
igneous
Red Quartzite River Pebble
Quartzite (SiO2 with iron oxide inclusions)
metamorphic
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Green Aventurine (Gua Sha tool)
Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)
metamorphic
Jasper Pebble
Silicon Dioxide (SiO2) - Microcrystalline Quartz with Iron Oxide Impurities
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
Pink Granite
Phaneritic Igneous Rock (high K-Feldspar content)
igneous
Clear Quartz
Silicon dioxide (SiO2)
mineral
Red Slag Glass
Amorphous Silica (Industrial byproduct with metallic oxide dopants)
Mineraloid / Industrial Byproduct
Pink agate (likely dyed or coated)
Microcrystalline quartz, SiO₂ (chalcedony/agate)
mineral
Green Glass Slag
Amorphous Silicon Dioxide (SiO2) with metal oxide impurities
mineraloid (man-made)
Green Aventurine and Clear Quartz
Green Aventurine (Silicon Dioxide - SiO2 with Fuchsite inclusions); Clear Quartz (Silicon Dioxide - SiO2)
Mineral
Green Agate
Silicon Dioxide (SiO2) - Chalcedony variety
mineral
Sandstone
Arenite
sedimentary
Gravel and Pavement Aggregates
Unconsolidated rock fragments / detrital sediments
sedimentary
Sandstone
Sedimentary Clastic Rock (Quartz Arenite)
sedimentary
Granite
Phaneritic Plutonic Felsic Rock (Granite)
igneous
Pink Granite
Phaneritic Felsic Igneous Rock (Granite)
igneous
Tumbled basalt (likely)
Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase feldspar and pyroxene, often with minor olivine and iron oxides
igneous
Fossiliferous Limestone Pebble
Sedimentary Rock (CaCO3)
sedimentary
Polished brecciated jasper
Jasper, opaque microcrystalline quartz (SiO₂), with iron-oxide and other mineral inclusions
gemstone
Sapphire
Corundum (Al2O3) with traces of Iron and Titanium
gemstone
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Gold Nugget
Native Gold (Au)
mineral
Pink Granite
Phaneritic Felsic Igneous Rock (Granite)
igneous
Dyed Agate Slice
Silicon Dioxide (SiO2) with artificial colorants
Mineral (variety of Chalcedony)
Granite cobble
Granite; chiefly quartz (SiO₂), feldspar, and mica/amphibole
igneous
Sandstone (Sedimentary Rock)
Arenite (SiO2 based)
sedimentary
Dyed Agate (Tumbled)
Silicon Dioxide (SiO2) - stained microcrystalline quartz
sedimentary
Green Slag Glass
Cullet (Amorphous Silicon Dioxide with impurities)
Man-made rock-like material
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
igneous
Blue Sapphire
Corundum (Al2O3 - Aluminum Oxide)
mineral
Likely tumbled dark volcanic rock
Probably basalt or basaltic andesite; exact identification is uncertain from the image
igneous
Pumice
Pumice (volcanic glass with vesicular texture)
igneous
Dark fine-grained rock, likely basalt
Basalt; chiefly plagioclase feldspar and pyroxene, commonly with olivine and iron oxides
igneous
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral