Yellow Agate
Agate (Varietal form of Chalcedony/Quartz, SiO2)
Category
Browse sedimentary or metamorphic (low grade) specimens identified by the Rock Identifier community.
Yellow Agate
Agate (Varietal form of Chalcedony/Quartz, SiO2)
Polished dark green stone, likely nephrite jade or serpentine
Nephrite jade: tremolite–actinolite amphibole, Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂; possible serpentine: Mg₃Si₂O₅(OH)₄
Biotite on Quartz
Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2) and Quartz (SiO2)
Sulfidic Mudstone with Pyrite/Goethite
Sulfidic Siltstone/Mudstone (FeS2)
Limonitic Iron Ore / Goethite
Hydrated Iron(III) oxide-hydroxide (primarily FeO(OH)·nH2O)
Gneiss
Gneiss (High-grade metamorphic rock)
Gneiss
Gneiss (Metamorphic Rock)
Gneiss
Foliated Metamorphic Rock
Gneiss
Gneissic Metamorphic Rock
Granite or Granitic Gneiss
Granitoid / Gneiss
Gneiss
High-grade metamorphic rock (Gneiss)
Banded Gneiss
Gneiss (High-grade Metamorphic Rock)
Gneiss
Gneiss (High-grade Metamorphic Rock)
Ferruginous Quartz (River Pebble)
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Banded gneiss (likely amphibolite-rich gneiss)
Banded gneiss; composition commonly quartz, feldspar, mica and/or amphibole
Beach Pebbles and Quartz Aggregates
Quartz pebbles and biogenic fragments (SiO2, CaCO3)
Mica Schist
Schist (muscovite/biotite rich regional metamorphic rock)
Anthracite Coal
Anthracite (Carbon-based sedimentary-metamorphic rock)
Gneiss (High-grade Metamorphic Rock)
Gneiss
Gneiss with Quartz/Feldspar Vein
Quartz-Feldspathic Gneiss
Pyrite
Iron Disulfide (FeS2)
Gneiss
Gneiss (Metamorphic Rock)
Gneiss
Gneissic Metamorphic Rock
Gneiss (Metamorphic Pebble)
Gneissic Metamorphic Rock
Gneiss
Gneissic Metamorphic Rock
Greenschist
Chlorite schist
Weathered mica-rich metamorphic rock
Probable biotite schist or mica schist
Gneiss
High-grade regional metamorphic Gneiss
Gneiss
Gneiss (High-grade Metamorphic Rock)
Gneiss
Gneiss
Gneiss (Granulite / Foliated Metamorphic Rock)
Gneiss
Gneiss (Banded Gneiss Cobble)
Gneiss
Gneiss
Gneiss
Gneiss (Banded Gneiss)
Gneiss
Anthracite Coal
Anthracite (Carbon Content: 86%–98%)
Gneiss
Gneiss (Metamorphic rock composed primarily of Quartz, Feldspar, and Mica/Amphibole)
Granitic Gneiss
Gneiss (Metamorphic rock of granitic composition)
Gneiss (with Quartz and Biotite Mica)
Gneiss
Muscovite Mica Schist
Muscovite Schist (KAl2(AlSi3O10)(OH)2)
Banded Gneiss
Gneiss
Gneiss
Gneissic Metamorphic Rock (Mineral composition: Quartz, Feldspar, Amphibole/Biotite)
Garnet Gneiss
Gneiss containing almandine-pyrope garnet