Garnet Schist
Almandine-Muscovite Schist
metamorphic
Category
Rock
Browse rock specimens identified by the Rock Identifier community.
Polished chalcedony with iron-oxide cap (probable carnelian/agate)
Microcrystalline quartz, SiO₂, with hematite/goethite inclusions
mineral
Quartz geode
Microcrystalline quartz (SiO₂), likely a small druzy quartz geode
mineral
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Quartz on Matrix
Silicon Dioxide (SiO2)
mineral
River cobble (Greywacke/Sandstone)
Sandstone / Greywacke
sedimentary
Granite (weathered, possibly porphyritic)
Granite; primarily quartz (SiO₂), feldspars, and mica/amphibole
igneous
Rounded sandstone pebble
Quartz-rich sandstone, likely arkosic or lithic sandstone
sedimentary
Greenstone, likely serpentinite
Serpentinite; predominantly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, chlorite, and talc
metamorphic
Weathered granite pebble
Granite, mainly quartz, feldspar, and mica; approximate composition SiO₂-rich continental crust
igneous
Glacial Cobble (likely Granitic or Gneissic)
Granite/Gneiss Glacial Erratic
igneous
Granite Pebble
Intrusive Igneous Rock
igneous
Fossil-bearing fine-grained sedimentary rock
Likely fossiliferous mudstone or shale; visible feature may be a plant fragment, trace fossil, or mineral vein
fossil
Mixed rounded river pebbles
Polymictic alluvial gravel; likely quartz/quartzite, chert, and weathered feldspathic rocks
sedimentary
Quartz Vein in Siltstone
Siltstone with Quartz (SiO2) inclusion
sedimentary
Quartz Geode with Chalcedony
Silicon Dioxide (SiO2) in Geode Form
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) within a geode
mineral
Serpentine
Antigorite, Lizardite, or Chrysotile (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4
metamorphic
Polished green stone, likely serpentine or altered basalt
Serpentine-group minerals, chiefly Mg₃Si₂O₅(OH)₄; exact identification requires testing
metamorphic
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Metaconglomerate
Protolith: Conglomerate (comprising SiO2, Al2O3, etc.)
metamorphic
Basalt with Calcite Veins
Basalt (Mafic Volcanic Rock)
igneous
Banded Gneiss
Gneiss (High-grade regional metamorphic rock)
metamorphic
Basalt
Basalt (Mafic volcanic rock)
igneous
Chalcedony Geode Fragment
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Quartz Druzy
Silicon Dioxide (SiO2)
mineral
Chalcedony / Agate Pebble
Silicon Dioxide (SiO2)
mineral
Agate
Cryptocrystalline quartz, Chalcedony (SiO2)
mineral
Jasper Pebble
SiO2 (Microcrystalline Quartz)
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Mixed River Pebbles and Jasper
Siliciclastic sediment and microcrystalline quartz
sedimentary
Sandstone (with secondary weathering/concretion)
Arenite (composed primarily of Quartz, SiO2)
sedimentary
Granite Pebble
Felsic Igneous Rock (Granitic composition)
igneous
Leopardite granite (likely)
Speckled granite; quartz–feldspar–biotite rock
igneous
Weathered granite (likely pink biotite granite)
Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende
igneous
Vein Quartz in Basalt or Mafic Rock
Silicon Dioxide (Quartz veins in volcanic host rock)
igneous
Rounded granite or granitic gneiss cobble
Granite; primarily quartz, feldspar, and mica (exact identification requires a fresh surface and testing)
igneous
Rounded sandstone pebble
Quartz-rich sandstone (likely arkosic or lithic sandstone)
sedimentary
Quartz Geode
Quartz (Silicon Dioxide - SiO2) within a Chalcedony and Limonite shell
sedimentary
Granite
Granite
Igneous
Banded Rock (likely Quartz-rich)
Uncertain, likely a Metamorphic Rock (e.g., Gneiss or Schist) with prominent Quartz and other minerals
Mineral
Pumice
Pumice (Volcanic Rock)
igneous