Feldspathic Gneiss
High-grade Metamorphic Rock (Gneiss)
metamorphic
Category
Not A Rock (Synthetic Material)
Browse not a rock (synthetic material) specimens identified by the Rock Identifier community.
Learn about Not A Rock (Synthetic Material) in the encyclopedia
View all →
Diorite
Diorite (plagioclase-rich phaneritic rock)
igneous
Banded Gneiss (River Cobble)
Gneiss (a high-grade metamorphic rock)
metamorphic
Siltstone with plant fossil impression
Sedimentary rock with Archaeopteris or Calamites flora impression
fossil
Limestone
Sedimentary rock composed mainly of calcite (CaCO3)
sedimentary
Claystone / Mudstone
Mudstone (Hydrous aluminum silicate rich rock)
sedimentary
Epidosite
Epidosite (Metasomatic calcium-aluminum silicate rock)
metamorphic
Sandstone (Ferruginous)
Arenite (Fe-bearing Clastic Sedimentary Rock)
sedimentary
Red Granite
Phaneritic Plutonic Rock (High Potassium Feldspar)
igneous
Sandstone (River Cobble)
Arenite
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Chert (Gray Chalcedony)
Microcrystalline Quartz (SiO2)
sedimentary
Nuummite
Nuummite (Orthorhombic amphiboles: Anthophyllite and Gedrite)
metamorphic
Quartz-bearing metamorphic rock, possibly epidote/quartzite
Quartz-rich rock with possible epidote and feldspar; exact identification requires testing
metamorphic
Sandstone (Weathered Pebble)
Arenite (primarily SiO2)
sedimentary
Sandstone (Red Arkose)
Sandstone (Arkose variant, primarily SiO2 with KAlSi3O8)
sedimentary
Jasper and Quartzite mix
Silicon Dioxide (SiO2) with impurities
sedimentary or metamorphic
Limestone
Calcareous sedimentary rock (CaCO3)
sedimentary
Basalt
Extrusive mafic igneous rock
igneous
Red Shale
Fissile Siliciclastic Sedimentary Rock
sedimentary
Unidentified dark reddish-brown rock or mineral specimen
Indeterminate from the blurred image; possibly iron-stained quartz, jasper, or a metallic sulfide-bearing rock
mineral
Chert (Common Opal/Agatized Rock)
Microcrystalline Quartz (SiO2) with potential Chalcedony/Opaline silica
sedimentary
Sandstone (Sedimentary Rock)
Arenite (SiO2 based)
sedimentary
Sandstone (Ferruginous)
Arenite with Iron oxide staining (SiO2 with Fe2O3)
sedimentary
Granite
Granite (composed mainly of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Dyed or treated turquoise-like tumbled stone
Likely turquoise (CuAl₆(PO₄)₄(OH)₈·4H₂O), though blue-green magnesite or howlite imitation is possible
mineral
Rounded basalt pebble
Basalt, aphanitic mafic volcanic rock; primarily plagioclase and pyroxene with possible olivine
igneous
Basalt
Basalt
igneous
Granodiorite (containing Biotite and Quartz)
Granodiorite (Plagioclase-rich phaneritic intrusive rock)
igneous
White Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Fine-grained dark igneous rock, likely basalt
Basalt; predominantly plagioclase feldspar and pyroxene, commonly with minor olivine and iron-titanium oxides
igneous
Basalt
Extrusive Mafic Igneous Rock (composed primarily of Plagioclase and Pyroxene)
igneous
Sandstone (Ferruginous)
Arenite (SiO2 with Fe2O3 inclusions)
sedimentary
Quartz / Quartzite
Quartz (Silicon Dioxide, SiO2)
metamorphic
Tumbled brown agate or jasper
Microcrystalline quartz, SiO₂ (likely chalcedony/agate with iron oxides)
mineral
Polished agate/jasper pebble
Microcrystalline quartz (chalcedony), SiO₂, with likely iron-oxide and clay inclusions
mineral
Likely iron-rich slag or weathered ironstone
Hematite–goethite-rich material (Fe₂O₃/FeO(OH)); possibly industrial iron slag
mineral
Jasper with Quartz Vein
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Geode (Unopened)
Silica-rich Concretion (primarily SiO2)
sedimentary
Quartzite
Quartzite (SiO2)
metamorphic
Tumbled Quartz
Silicon Dioxide (SiO2)
mineral
Chert (Arrowhead or Projectile Point)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary