Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Category
Metamorphic (Altered Igneous Rock)
Browse metamorphic (altered igneous rock) specimens identified by the Rock Identifier community.
Aventurine (likely Green Aventurine)
Silicon Dioxide (SiO2) with mineral inclusions
Mineral/Mineraloid within a rock matrix
Gneiss
Gneiss
metamorphic
Quartz (Milky Quartz)
Silicon Dioxide (SiO₂)
mineral
Gemstone Sand (Mineral Assortment)
Mixed Mineral Concentrates (Commonly including Quartz SiO2, Garnet X3Y2(SiO4)3, and Tourmaline (Na,Ca)(Li,Mg,Al)3(Al,Fe,Mn)6(BO3)3(Si6O18)(OH,F)4)
mineral
Ferruginous Quartz Cobble
Silicon Dioxide (SiO2) with Iron Oxide inclusions
mineral
Milky Quartz (Vein Quartz)
Silicon Dioxide (SiO2)
mineral
Milky Quartz (Druzy Geode fragment)
Silicon Dioxide (SiO2)
mineral
Gneiss
Gneiss
metamorphic
Arkosic Sandstone (or Conglomeritic Sandstone fragment)
Arkose (rich in feldspar)
sedimentary
Black Tourmaline (Schorl)
Schorl (Sodium iron silicate hydroxide boron silicate); NaFe3Al6(BO3)3Si6O18(OH)4
mineral
Smoky Quartz
Smoky Quartz (Silicon Dioxide - SiO2)
mineral
Spessartine Garnet in Quartz/Feldspar Pegmatite
Spessartine (Mn3Al2(SiO4)3) in Quartz (SiO2) and Feldspar
Mineral in Igneous Rock
Clear Quartz Sphere
Quartz (Silicon Dioxide, SiO2)
mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Gneiss
Gneiss
metamorphic
Turquoise
Hydrated phosphate of copper and aluminum (CuAl6(PO4)4(OH)8·4H2O)
mineral
Mica Schist
Mica Schist (primarily Muscovite or Biotite sheet silicates)
metamorphic
Gneissic River Pebble
Gneiss
metamorphic
Gneiss (Metamorphic Rock)
Gneiss
metamorphic
Quartz (Milky or Clear variety)
Silicon Dioxide (SiO2)
mineral
Gneiss
Gneiss (High-grade Metamorphic Rock)
metamorphic
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Banded Gneiss
Gneiss (High-grade regional metamorphic rock)
metamorphic
Serpentinite
Serpentinite (composed primarily of serpentine group minerals like lizardite, chrysotile, or antigorite; Mg3Si2O5(OH)4)
metamorphic
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Gneiss
Gneiss
metamorphic
Quartz with Mica inclusions (likely Schist or Gneiss host)
Silicon Dioxide (SiO2) with Phyllosilicates (KAl2(AlSi3O10)(OH)2)
metamorphic
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Quartz (Vein Quartz)
Silicon Dioxide (SiO2)
mineral
Black Onyx
Silicon Dioxide (SiO2) with parallel banding
mineral
Unidentifiable Specimen
Undetermined
Unknown
Milk Quartz (White) and Yellow Aventurine (Yellow)
Silicon Dioxide (SiO2)
mineral
Ruby (Pinkish-Red)
Corundum (Al2O3 with Chromium trace)
mineral
Sunstone
Oligoclase or Andesine (Labradorite) Feldspar (Na,Ca)(Si,Al)4O8
mineral
Smoky Quartz (Tumbled)
Silicon Dioxide (SiO2)
mineral
Gneiss
Gneiss (High-grade Metamorphic Rock)
metamorphic
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic