Pumice
Pumice (Silicic volcanic glass with vesicular structure)
igneous
Category
Not A Natural Rock
Browse not a natural rock specimens identified by the Rock Identifier community.
Learn about Not A Natural Rock in the encyclopedia
View all →
Serpentine-rich serpentinite pebble
Serpentinite, composed chiefly of serpentine-group minerals (lizardite, antigorite, chrysotile), commonly with magnetite and minor brucite
metamorphic
Pea Gravel / River Gravel
Unconsolidated Clastic Sedimentary Aggregate
sedimentary
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Granite
Phaneritic intrusive igneous rock
igneous
Quartz Geode (Smoky Quartz)
Silicon Dioxide (SiO2)
mineral
Amethyst Geodes
Silicon Dioxide (Quartz with Iron impurities), SiO2
mineral
Blue Sapphire (Tumbled/Polished)
Corundum (Al2O3)
mineral
Black Onyx
Silicon Dioxide (SiO2) with parallel banding
mineral
Silty Shale or Mudstone
Siltstone/Mudstone (Clastic Sedimentary Rock)
sedimentary
Granite cobble
Granite; chiefly quartz (SiO₂), feldspar, and mica/amphibole
igneous
Tumbled quartz-rich pebble
Microcrystalline quartz (SiO₂), possibly weathered chert or chalcedony
mineral
Granite
Granite (Felsic Plutonic Rock)
igneous
Boulder Opal
Precious Opal in Ironstone (Amorphous Hydrated Silica, SiO2·nH2O)
Mineral
Basalt Pebble
Basalt (Mafic Extrusive Igneous Rock)
igneous
Mixed collection of natural stones
Several unidentified lithologies, likely including basalt, granite, quartzite, sandstone, and weathered metamorphic rocks
igneous, metamorphic, sedimentary
Red Quartzite River Pebble
Quartzite (SiO2 with iron oxide inclusions)
metamorphic
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite
sedimentary
Quartz Crystal Cluster on Matrix
Silicon Dioxide (SiO2)
mineral
Green Aventurine
Silicon Dioxide (SiO2) with Fuchsite inclusions
metamorphic
Rounded river or beach pebble
Likely quartz-rich sandstone or quartzite; exact identification requires a close-grained view and hardness test
sedimentary
Quartzite
Quartzite (SiO2)
metamorphic
Pumice
Pumice (Amorphous volcanic glass)
igneous
Dyed Blue Agate
Silicon Dioxide (SiO2)
Mineral
Fossiliferous Limestone Pebble
Sedimentary Rock (CaCO3)
sedimentary
Chert / Flint Pebble with Fossil Cavity
Silicon Dioxide (SiO2)
sedimentary
Sandstone
Arenite
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Green Quartzite
Quartzite (SiO2 with chlorite/epidote inclusions)
metamorphic
Sandstone (likely Fossiliferous)
Arenite / Fossiliferous Sandstone (SiO2 composition)
sedimentary
Red jasper (tumbled river pebble)
Jasper, an opaque microcrystalline variety of quartz/chalcedony (SiO₂), colored mainly by iron oxides
mineral
Amethyst
Crystalline Silicon Dioxide with iron impurities (SiO2)
gemstone
Clear Quartz
SiO2 (Silicon Dioxide)
mineral
Emerald in Matrix (Quartz/Schist)
Beryl (Be₃Al₂Si₆O₁₈) with Chromium/Vanadium impurities
mineral
Green Aventurine
Quartzite with Fuchsite inclusions (SiO2)
metamorphic
Likely foliated metamorphic rock, possibly schist
Mica schist or micaceous quartzite; exact identification is uncertain from the photograph
metamorphic
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Granite
Phaneritic Igneous Rock (composed primarily of Quartz, Feldspar, and Mica)
igneous
Granite
Granite (Felsic Plutonic Rock)
igneous
Sandstone
Sandstone (principally SiO2)
sedimentary
Sandstone (Ferruginous)
Arenite (composed primarily of SiO2 with Fe2O3 staining)
sedimentary