Porphyry
Porphyritic Andesite / Basaltic Porphyry
igneous
Category
Synthetic (Not A Natural Rock)
Browse synthetic (not a natural rock) specimens identified by the Rock Identifier community.
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Blue Agate (Dyed)
Silicon Dioxide (SiO2)
mineral
Pumice (Vesicular Lava)
Pumice
igneous
Granite
Granite (interlocking crystals of quartz, feldspar, and mica)
igneous
Sandstone
Arenite (SiO2 primarily)
sedimentary
Asphalt Concrete
Bituminous conglomerate
sedimentary
Sandstone
Arenite (SiO2 based typically)
sedimentary
Sandstone
Sedimentary quartz arenite
sedimentary
Yellow Quartz (Citrine-colored Quartz Pebble)
Silicon Dioxide (SiO2)
mineral
Porphyritic Basalt or Spotted Pebble
Porphyritic volcanic rock with phenocrysts
igneous
Polished Tumbled Stone (Dark Chalcedony / Jasper)
Silicon Dioxide (SiO2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Red Jasper
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Sandstone (Ferruginous)
Arenite (Fe-rich SiO2)
sedimentary
Smoky Quartz
Silicon Dioxide (SiO2) with aluminum impurities
mineral
Ventifact
Eolian Ventifact (often composed of basalt, chert, or quartzite)
sedimentary
Shale
Sedimentary rock composed of clay minerals and quartz
sedimentary
Sandstone (Ferruginous)
Arenite with Iron-Oxide Cement
sedimentary
Quartz (Water-worn pebble)
Silicon Dioxide (SiO2)
mineral
Clear Quartz (Milky Quartz pebble)
Silicon Dioxide (SiO2)
mineral
River Stone (Sandstone with Oxide Banding)
Arenite with Iron/Manganese Oxide inclusions
sedimentary
Basalt
Basalt (Mafic Extrusive Igneous Rock)
igneous
Sandstone
Arenite (SiO2 based)
sedimentary
Tumbled blue stone, likely blue aventurine or dyed quartzite
Quartz (SiO₂), likely with inclusions or artificial dye; exact identification requires testing
mineral
Sandstone Flagstone
Arenite (SiO2 with various cementing agents)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone (Red Sandstone)
Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide)
sedimentary
Smoky Quartz (with possible Feldspar inclusions)
Silicon Dioxide (SiO2)
mineral
Note: Item is not a geological specimen
Guitar Components (Steel, Nickel, Plastic, Wood)
Synthetic/Consumer Product
Granite
Phaneritic Felsic Igneous Rock (composed of quartz, feldspar, and mica)
igneous
Vesicular Basalt
Vesicular Basalt (Mafic Volcanic Rock)
igneous
Basalt Pebble
Basalt
igneous
Polished blue banded agate cabochon/ornamental slab
Microcrystalline quartz (chalcedony), SiO₂, with blue coloring or inclusions
mineral
Sandstone
Arenite (SiO2 main component)
sedimentary
Sandstone (Ferruginous)
Arenite (primarily SiO2 with iron oxide staining/cementing)
sedimentary
Quartzite
Quartzite (SiO2)
metamorphic
Possible tektite or iron-rich slag-like natural specimen
Uncertain; possibly natural glass (tektite) or magnetite-rich rock
mineral
Pebble
Lithic fragment / Weathered rock fragment
sedimentary
Shale
Mudstone (composed primarily of clay minerals like kaolinite, illite, and smectite, with quartz and calcite)
sedimentary
Sandstone with Iron Staining
Arenite with Limonite/Hematite inclusions (SiO2 + Fe2O3/FeO(OH))
sedimentary
Shale
Shale (clay-rich mudstone)
sedimentary
Amethyst Geode
Quartz (Silicon Dioxide, SiO2)
mineral