Quartz with inclusions (likely Tourmaline or Biotite)
Silicon Dioxide (SiO2)
mineral
Category
Amorphous Solid
Browse amorphous solid specimens identified by the Rock Identifier community.
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Hematite
Iron Oxide (Fe2O3)
mineral
Quartzite Pebble
Metamorphic Quartz Sandstone (SiO2)
metamorphic
Quartzite Pebble
Quartzite (SiO2)
metamorphic
Quartzite (Sugar Quartz)
Quartzite (primarily SiO2)
metamorphic
Quartzite (Beach Pebble)
Quartzite (Composition: SiO2)
metamorphic
Black Onyx
Cryptocrystalline Quartz (SiO2) with impurities
mineral
Quartzite
Quartzite (primarily SiO2)
metamorphic
Quartzite Pebble (River Rock)
Quartzite (primarily SiO2)
metamorphic
Quartzite (Iron-stained)
Quartzite (SiO2 with Fe2O3 staining)
metamorphic
Quartzite
Quartzite (Primary mineral: SiO2)
metamorphic
Quartz-veined Mudstone or Argillite
SiO2 (Quartz) in Siltstone/Mudstone matrix
sedimentary
Quartzite
Quartzite (primarily SiO2)
metamorphic
Vesicular Basalt / Lava Rock
Extrusive mafic igneous rock (Mafic silicate)
igneous
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
sedimentary
Red Jasper (Tumbled)
Silicon Dioxide (SiO2)
sedimentary
Amethyst Geode
Amethyst (Silicon Dioxide), Formula: SiO2
mineral
Polished pink chalcedony (likely pink agate/geode)
Microcrystalline quartz, SiO₂; chalcedony with iron-bearing inclusions and possible druzy quartz
mineral
Geode (Unopened Keokuk Geode)
Silicon Dioxide (SiO2) - Chalcedony / Quartz exterior
mineral
Biotite on Quartz
Biotite Mica (K(Mg,Fe)3AlSi3O10(F,OH)2)
mineral
Bismuth Crystal
Bismuth (Bi)
mineral
Blue Agate (Dyed Chalcedony)
Silicon Dioxide (SiO2)
mineral
Blue Quartzite
Quartzite (primarily SiO2 with inclusions like Dumortierite or Magnesio-riebeckite)
metamorphic
Greenstone / Serpentinite
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)3(Si, Al, Fe)2O5(OH)4
metamorphic
Geode (Unopened)
Siliceous Concretion / Geode
sedimentary
Dark volcanic sand / basaltic sand
Basalt-derived lithic sand, chiefly plagioclase, pyroxene, and volcanic glass
igneous
Lunar Meteorite (Feldspathic Breccia)
Achondrite, Lunar Meteorite (Feldspathic Breccia)
igneous
Quartz Vein in Schist
Quartz (SiO2) in Mica Schist
metamorphic
Gastropod Fossil (Snail Internal Mold)
Gastropoda; internal mold (steinkern), often composed of Calcium Carbonate (CaCO3) or Silica (SiO2)
sedimentary
Shale with Vein Infillings
Shale (a fine-grained clastic sedimentary rock). The veins could be Calcite (CaCO3), Quartz (SiO2), or other minerals.
Sedimentary Rock
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Quartzite
Quartzite (SiO2)
metamorphic
Quartzite
Quartzite (SiO2 silicon dioxide)
metamorphic
Black Onyx (Tumbled)
Silicon Dioxide (SiO2)
mineral
Green Aventurine
Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2AlSi3O10(OH)2)
mineral
Epidote (Greenstone)
Epidote (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH))
metamorphic
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Porphyritic Basalt (or Porphyry)
Porphyritic Basalt (Mafic volcanic rock with phenocrysts)
igneous
Agate Geode / Nodular Chalcedony
Silicon Dioxide (SiO2) with impurities
mineral
Vesicular basalt (likely scoria)
Mafic volcanic rock; predominantly plagioclase, pyroxene, and volcanic glass, with possible olivine
igneous
Geode Nodules / Keokuk Geode
Quartz / Chalcedony Geode (SiO2)
sedimentary
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
metamorphic