Banded Iron Formation (Fragment)
Banded Iron Formation (BIF)
sedimentary
Category
Mineral_rock
Browse mineral_rock specimens identified by the Rock Identifier community.
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Amethyst
Quartz (Silicon Dioxide, SiO2)
gemstone
Lake Superior Agate
SiO2 (Quartz variety chalcedony)
gemstone
Quartz Geode
Silicon Dioxide (SiO2)
sedimentary
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
mineral
Weathered mafic rock, likely basalt
Basalt; primarily plagioclase feldspar, clinopyroxene, and commonly olivine or magnetite
igneous
Gneiss
Metamorphic rock of high-grade regional metamorphism
metamorphic
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Vesicular Basalt (Lava Rock)
Vesicular Basalt
igneous
Serpentine
Antigorite, Lizardite, or Chrysotile (Mg3Si2O5(OH)4)
metamorphic
Pet Rock (Quartzite/Sandstone River Rock)
Silicon Dioxide (SiO2) mixture
sedimentary
Quartz with Iron Staining and Chlorite Inclusions
Silicon Dioxide (SiO2)
mineral
Graphite
Graphite (Carbon, C)
mineral
Inukshuk Rock Sculpture (composed of Granite, Slate, and Amethyst)
Silicon Dioxide (Amethyst portion, SiO2) with mixed silicate rock assemblage
mineral
Septarian Nodule
Septarian Concretion (Calcite, Aragonite, and Limestone)
sedimentary
Granite / Gneiss Ballast Rock
Granite (Quartzo-feldspathic rock)
igneous
Tourmaline-bearing pegmatite
Quartz–feldspar pegmatite with black schorl tourmaline; minor mica likely present
igneous
Weathered green-gray stone, likely serpentinite or chlorite-rich metamorphic rock
Probable serpentinite (antigorite–lizardite), possibly chlorite schist or altered basalt
metamorphic
Sandstone
Sedimentary Rock (Quartz arenite)
sedimentary
Sandstone Pebble
Sedimentary Rock (Quartzose Sandstone)
sedimentary
Granite
Felsic intrusive igneous rock
igneous
Granite
Felsic intrusive igneous rock
igneous
Granite
Felsic intrusive igneous rock
igneous
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Fossiliferous Sedimentary Rock
Sedimentary Rock with Invertebrate Fossil Imprint
fossil
Sandstone (Fluvial Pebble)
Arenite
sedimentary
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
mineral
Quartz-rich pegmatite with mica and dark inclusions
Pegmatite; chiefly quartz (SiO₂), with feldspar and biotite/tourmaline inclusions
igneous
Unidentified weathered rock fragments
Likely mixed silicate rocks; specific identification requires testing
mineral
Quartz Rock
Silicon Dioxide (SiO2)
mineral
Obsidian
Volcanic glass (SiO2 + impurities)
igneous
Weathered quartz-rich rock fragment
Likely quartz-bearing feldspathic rock; exact identification requires testing
mineral
Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
sedimentary
Tiger's Eye
Quartz pseudomorph after crocidolite (SiO2)
mineral
Hematite
Iron(III) oxide, Fe2O3
mineral
Larimar
Pectolite (NaCa2Si3O8(OH))
gemstone
Clear Quartz (Faceted)
Silicon Dioxide (SiO2)
gemstone
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Likely iron-rich rock or metallic mineral fragment
Uncertain; possibly limonite/goethite-rich material or weathered iron meteorite fragment
mineral
Red Sandstone
Arenite (primarily quartz with iron oxide cement)
sedimentary
Sandstone and River Pebbles
Sedimentary Rock (Sandstone / Quartzite / Chert)
sedimentary