Agate Geode
Silicon Dioxide (SiO2) - Chalcedony variety
sedimentary
Category
Man Made Rock (Technosol)
Browse man made rock (technosol) specimens identified by the Rock Identifier community.
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Basalt (Porphyritic Basalt)
Extrusive Igneous Rock
igneous
Dalmatian Stone
Aplite (often incorrectly called Dalmatian Jasper)
igneous
Serpentine
Antigorite/Lizardite/Chrysotile group, Mg3Si2O5(OH)4
metamorphic
Pink Granite
Phaneritic Felsic Igneous Rock (composed primarily of Quartz and Potassium Feldspar)
igneous
Granite fragment
Granite
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
Unakite
Epidotized Granite
metamorphic
Porphyritic Basalt (River Rock)
Porphyritic Basalt
igneous
Quartz Vein in Gneiss or Basalt
Milky Quartz (SiO2) within Metamorphic Host Rock
Metamorphic or Igneous with Mineral Inclusion
Desert Varnish on Sandstone
Ferromanganese coating on Quartz Arenite
sedimentary
Basalt
Mafic extrusive igneous rock
igneous
Herkimer Diamond
Quartz (Silica - SiO2)
mineral
Shale
Shale (Fine-grained clastic sedimentary rock)
sedimentary
Vuggy Quartz on Matrix
Crystalline Silicon Dioxide (SiO2)
mineral
River Rocks (Black)
Various lithologies (e.g., basalt, chert, obsidian for black varieties), mechanically rounded clasts
Sedimentary
Coal
Coal (Sedimentary Rock / Organic Rock)
sedimentary
Sandstone (with potentially high Feldspar/Arkose content)
Clastic sedimentary rock (SiO2 dominated)
sedimentary
Granite
Granite
Igneous
Weathered garnet-bearing gneiss
Quartz–feldspar–mica gneiss with almandine garnet, chiefly Fe₃Al₂(SiO₄)₃
metamorphic
Quartz Vein in Matrix
Silicon Dioxide (SiO2) within Rhyolitic or Granitic Matrix
igneous
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
Hag Stone (Adder Stone / Geode-bearing Pebble)
Sedimentary Rock with Cavity (often Quartzite, Limestone, or Sandstone)
sedimentary
Sandstone (with Iron Staining)
Arenite (primarily SiO2 with Fe2O3/FeO(OH) oxides)
sedimentary
Vesicular Basalt with Quartz/Chalcedony
Vesicular Basalt (primarily Plagioclase, Pyroxene, and Olivine with SiO2 infill)
igneous
Basalt
Extrusive mafic igneous rock
igneous
Basalt with Quartz/Calcite Veining
Basalt (principally Plagioclase and Pyroxene)
igneous
Granite
Granite
Igneous
Druzy Quartz on Matrix
Silicon Dioxide (SiO2)
mineral
Weathered Sandstone or Siltstone
Sedimentary Rock
sedimentary
Orbicular granite (likely rapakivi-type granite)
Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende
igneous
Slickenside
Tectonic Fault Scarp Surface
metamorphic
Basalt
Extrusive Igneous Rock
igneous
Basalt
Mafic Igneous Rock (composed primarily of pyroxene and calcium-rich plagioclase)
igneous
Basalt pebble
Aphanitic Mafic Volcanic Rock (Fe/Mg rich)
igneous
Quartz Vein in Host Rock
Hydrothermal Quartz (SiO2) in Slates/Schists
metamorphic