Shale
Shale (Sedimentary rock composed of mud/clay minerals)
sedimentary
Category
Mineral, Possibly Rock Fragment Containing A Mineral
Browse mineral, possibly rock fragment containing a mineral specimens identified by the Rock Identifier community.
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Gneiss (foliated metamorphic rock)
Gneiss
metamorphic
Granite
Granite (High-silica plutonic rock)
Igneous
Pegmatite
Igneous Pegmatite (felsic intrusive rock)
igneous
Amethyst (Agate/Chalcedony variety)
Silicon Dioxide (SiO2) with iron impurities
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Fossil shark tooth
Likely fossilized shark tooth, possibly Carcharhinus or Otodus species
fossil
Note: Item is not a geological specimen
n/a
none
Poppy Jasper
Microcrystalline Quartz (SiO2) with mineral inclusions
sedimentary
Granite (Weathered)
Phaneritic Felsic Igneous Rock
Igneous
Sandstone Cobble
Arenite (Secondary classification based on grain size)
sedimentary
Fossiliferous Limestone
Biomicrite / Fossiliferous Limestone (CaCO3)
fossil
Likely basalt or vesicular volcanic rock
Basalt, possibly scoriaceous basalt; exact identification is uncertain from the photograph
igneous
Quartz (Microcrystalline/Gravel)
Silicon Dioxide (SiO2)
mineral
Fossil plant impression, likely fern or leaf
Indeterminate fossilized vascular-plant compression; possibly a fern frond or other Paleozoic plant
fossil
Sandstone (River Pebble)
Arenite (primarily SiO2)
sedimentary
Hag Stone (Adder Stone / Geode-bearing Pebble)
Sedimentary Rock with Cavity (often Quartzite, Limestone, or Sandstone)
sedimentary
Green Aventurine
Quartz (Silicon Dioxide, SiO2) with fuchsite inclusions
mineral
Granite
Felsic intrusive igneous rock
igneous
Sandstone (Quartzose Sandstone)
Clastic Sedimentary Rock (primarily SiO2)
sedimentary
Granite Gravel / Crushed Granite
Plutonic Felsic Igneous Rock
igneous
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with Bioclastic inclusions
sedimentary
Peridotite
Peridotite (Ultramafic Rock)
igneous
Pebble or Cobble (likely composed of sandstone or conglomerate)
Clastic Sedimentary Rock (specific name like sandstone, conglomerate, or breccia would require microscopic analysis of clast size and angularity)
Sedimentary Rock (possibly a conglomerate or coarse-grained sandstone)
Sandstone Concretion
Ferruginous Sandstone Concretion
sedimentary
Weathered granite or granitic gneiss fragment
Granite, predominantly quartz, feldspar, and dark mica/amphibole
igneous
Pebble
Lithic fragment / Sedimentary clast
sedimentary
Unidentified gray rock/mineral specimen
Indeterminate; possibly quartz-rich rock or a metallic sulfide-bearing specimen
mineral
Likely gray granite fragment
Granite, composed mainly of quartz, feldspar, and mica
igneous
Granite
Intrusive Igneous Rock (Mainly Quartz, Feldspar, and Mica)
igneous
Lake Superior Agate
Chalcedony (SiO2 with iron impurities)
mineral
Dendritic Agate
Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions
mineral
Pegmatite
Igneous Pegmatite
igneous
Vesicular Basalt with Amygdules
Amygdaloidal Basalt
igneous
Granite fragment
Felsic intrusive igneous rock; mainly quartz, alkali feldspar, plagioclase, and minor biotite/hornblende
igneous
Shungite
Fullerene-bearing carbonaceous rock
mineral
Basalt
Extrusive Igneous Rock
igneous
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Gneiss with Quartz Veining
Gneiss (High-grade metamorphic rock)
metamorphic
Moss Agate
Chalcedony (Silicon Dioxide) with dendritic inclusions (SiO2)
mineral
Porphyritic Basalt
Porphyritic Basalt
igneous
Basalt
Basalt (Mafic Extrusive Igneous Rock)
igneous