Rough Precious Opal
Hydrated Silica (SiO2·nH2O)
mineral
Category
Igneous Or Sedimentary (Anthropogenic Modification)
Browse igneous or sedimentary (anthropogenic modification) specimens identified by the Rock Identifier community.
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Chalcedony (Agate Pebble)
Microcrystalline Quartz (SiO2)
sedimentary
Chalcedony (Agate)
Cryptocrystalline Quartz (SiO2)
mineral
Turquoise
Hydrated phosphate of copper and aluminum - CuAl6(PO4)4(OH)8·4H2O
mineral
Chalcedony (Carnelian Agate pebble)
Silicon Dioxide (SiO2)
mineral
Quartz (Crystalline Cluster)
Silicon Dioxide (SiO2)
mineral
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Banded Gneiss
Gneiss (Metamorphic rock of variable mineralogy, often quartz-feldspar base)
metamorphic
Carnelian
Silicon Dioxide (SiO2) - variety of Chalcedony
mineral
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Foliated Gneiss (River-Worn Pebble)
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Quartz Geode (Nodule)
Silicon Dioxide (SiO2)
sedimentary or igneous
Greenstone (Greywacke or Nephrite Jade variant)
Metamorphosed mafic igneous or sedimentary rock (e.g., Actinolite-Chlorite Schist)
metamorphic
Gneiss
Gneiss
metamorphic
Banded Gneiss with Quartz Vein
Gneiss containing SiO2 (Quartz) intrusion
metamorphic
Gneiss
Gneiss
metamorphic
Banded Gneiss
Metamorphic Gneiss (High-grade regional metamorphism specimen)
metamorphic
Gneiss
High-grade Metamorphic Gneiss
metamorphic
Banded Gneiss
Gneiss (Metamorphic Rock)
metamorphic
Pyrite
Iron Sulfide (FeS2)
mineral
Banded gneiss pebble
Gneiss, likely quartz–feldspar–mica gneiss
metamorphic
Blue Chalcedony
Microcrystalline Quartz (SiO2)
mineral
Turquoise (possible Dyed Magnesite/Howlite)
CuAl6(PO4)4(OH)8·4H2O
mineral
Gneiss
Gneiss (Metamorphic high-grade)
metamorphic
Gneiss (specifically a Banded Gneiss cobble)
Gneiss (composed mainly of Quartz, Feldspar, and Biotite/Amphibole)
metamorphic
Carnelian
Carnelian (SiO2, Silicon Dioxide with Iron Oxide impurities)
mineral
Quartz Druzy
Crystalline Silicon Dioxide (SiO2)
mineral
Gneiss
Gneiss
metamorphic
Ferrochrome Slag
Anthropogenic silicate/oxide glass (Complex silicate matrix with Cr-Fe-Si inclusions)
Industrial byproduct (often confused with igneous rocks or meteorites)
Banded Gneiss
Gneiss (High-grade regional metamorphic rock)
metamorphic
Feldspathic Gneiss
Feldspathic Gneiss (High-grade regional metamorphic rock)
metamorphic
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Gneiss
Foliated Metamorphic Rock (Gneiss)
metamorphic
Asphalt (Road Aggregate)
Asphalt concrete / Bituminous mixture
anthropogenic sedimentary (technolith)
Quartz Druze on Matrix (Geode Fragment)
Quartz (Silicon Dioxide, SiO2)
mineral
Carnelian
Carnelian (a variety of Chalcedony); SiO2 (Silicon Dioxide)
mineral
Banded Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Gneiss (Schistose)
Gneiss
metamorphic
Carnelian
Carnelian (Silicon Dioxide - SiO2)
mineral
Carnelian
Cryptocrystalline Quartz (SiO2 with iron oxide impurities)
mineral
Banded Gneiss
Gneiss (Metamorphic Rock)
metamorphic
Blue-dyed Quartz Druzy
Silicon Dioxide (SiO2) with artificial pigment
mineral