Phyllite (possibly low-grade greenish slate)
Foliated metamorphic rock composed mainly of very fine-grained quartz, mica, and chlorite; approximate composition varies and has no single fixed chemical formula
metamorphic
Category
Sedimentary Rock (Possibly Composed Of Various Minerals)
Browse sedimentary rock (possibly composed of various minerals) specimens identified by the Rock Identifier community.
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Sandstone (Iron-stained)
Arenite (composed predominantly of SiO2)
sedimentary
Mixed Tumbled Stones Collection
Mixed Silicates and Carbonates (Quartz, Amorphous Silica, Carbonates)
multiple
Sandstone
Arenite (SiO2 primarily)
sedimentary
Weathered basalt cobble
Basalt, a fine-grained mafic volcanic rock
igneous
Banded metamorphic rock, likely gneiss
Biotite–quartz–feldspar gneiss, possibly migmatitic
metamorphic
Pyrite in Matrix
Iron Disulfide (FeS2)
mineral
Red Sandstone Pebble
Sedimentary quartz sandstone
sedimentary
Druzy Quartz
Silicon Dioxide (SiO2)
mineral
Conglomerate
Conglomerate
sedimentary
Sandstone (Painted)
Arenite (primarily SiO2)
sedimentary
Quartz-rich rock, possibly milky quartz or quartzite
Quartz (SiO₂); if quartzite, recrystallized quartz sandstone
metamorphic
Sandstone
Arenite
sedimentary
Druzy Quartz
Crystalline Silicon Dioxide (SiO2)
mineral
Mixed River Pebbles
Clastic Sedimentary Alluvial Deposit / Polymictic Conglomerate Clasts
sedimentary
Siltstone River Rock
Siltstone (composed of silt-sized particles, silicate minerals)
sedimentary
Metal Chain Belt with Square Plates
Not applicable (man-made)
Man-made Object (Metalwork)
Sandstone
Sedimentary rock composed mainly of quartz sand
sedimentary
Jasper-rich breccia (likely iron-stained jasper)
Silicified breccia composed mainly of microcrystalline quartz (SiO₂), with hematite/goethite and possibly iron-rich clay minerals
sedimentary
Fossil Coral
Fossilized Scleractinia or Tabulata (various genera/species)
Sedimentary
Conglomerate
Conglomerate (SiO2 matrix with various silicate clasts)
sedimentary
Possibly banded ironstone (iron-rich metamorphic rock)
Likely iron formation, composed chiefly of hematite or goethite with silica-rich layers; exact identification is uncertain from the photo
metamorphic
Sandstone
Sedimentary Rock (Quartz arenite)
sedimentary
Sandstone
Sandstone (lithified arenite/wacke)
Sedimentary Rock
Likely garnet-bearing schist
Garnet mica schist; commonly quartz + mica (muscovite/biotite) ± garnet
metamorphic
Sandstone
Sedimentary Clastic Rock
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Sandstone
Clastic Sedimentary Rock
sedimentary
Weathered chert or siliceous limestone
Microcrystalline quartz (SiO₂), possibly with carbonate minerals
sedimentary
Conglomerate
Clastic conglomerate (rounded pebble- to cobble-sized clasts in a finer matrix)
sedimentary
Greenstone / altered mafic rock
Likely chlorite–actinolite schist or metabasalt; exact identification requires testing
metamorphic
Biotite Granite
Phaneritic Felsic Igneous Rock
igneous
Weathered volcanic rock, possibly andesite
Likely andesite; identification is provisional from the photograph
igneous
Slate
Foliated Metamorphic Rock (composed of quartz, illite, and chlorite)
metamorphic
Quartz pebble
Silicon dioxide (SiO2)
mineral
Rounded sandstone pebble
Quartz-rich sandstone; commonly arkose or lithic sandstone
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone Concretion
Sedimentary concretion
Sedimentary
Agate Geode
Silicon Dioxide (SiO2) - Chalcedony variety
sedimentary
Mixed Rock and Mineral Collection
Various geological specimens
igneous, sedimentary, and metamorphic
Clear quartz chips
Quartz (silicon dioxide, SiO₂)
mineral
Quartz Crystal
Silicon Dioxide (SiO2)
mineral