Quartz pebble
Silicon dioxide (SiO2)
mineral
Category
Igneous Rock (Volcanic Glass)
Browse igneous rock (volcanic glass) specimens identified by the Rock Identifier community.
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Quartz Pebble
Quartz (SiO2)
sedimentary
Vein-filled Porphyry or Brecciated Jasper Pebble
Brecciated volcanic rock with quartz/calcite veins
igneous
Vesicular Basalt (Aqueous Tumbled)
Scoriaceous Basalt
igneous
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Basalt
Basalt (extrusive igneous rock)
Igneous
Diabase (Dolerite) Cobble
Diabase / Dolerite
igneous
Basalt with Epidote (Porphyry)
Basalt (with inclusions of Epidote/Feldspar)
igneous
Obsidian
Obsidian (Volcanic Glass, SiO2)
igneous
Vesicular Basalt (Scoria)
Mafic extrusive volcanic rock (predominantly Plagioclase feldspar and Pyroxene)
igneous
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Basalt
Basalt
igneous
Granodiorite
Granodiorite (containing Plagioclase, Quartz, K-Feldspar, and Hornblende or Biotite)
igneous
Agate Bookend / Quartz Geode
Silicon Dioxide (SiO2)
mineral
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Basalt
Mafic Volcanic Rock (Primarily Plagioclase feldspar and Pyroxene)
Igneous
Weathered quartz-rich granitoid (likely granite or granodiorite)
Granite–granodiorite; chiefly quartz (SiO₂), feldspar, and minor mica/amphibole
igneous
Amygdaloidal Basalt
Basalt with secondary mineral infilling (commonly SiO2 or Zeolites)
igneous
Basalt
Basalt (Mafic Extrusive Igneous Rock)
igneous
Lace Agate (specifically Red Lace Agate)
Silicon Dioxide (SiO2) - variety of Chalcedony/Quartz
Mineral
Granodiorite
Granodiorite (Intermediate intrusive igneous rock)
igneous
Basalt
Basalt (Mafic Extrusive Igneous Rock)
igneous
Greenstone Porphyry
Porphyritic Metavolcanic Rock
igneous
Granite
Granite (Felsic intrusive igneous rock)
igneous
Basalt
Basalt (Mafic Extrusive Igneous Rock)
igneous
Greenstone
Metamorphosed Mafic Igneous Rock
metamorphic
Vesicular basalt (likely weathered lava rock)
Vesicular basalt; primarily plagioclase feldspar, pyroxene, and volcanic glass, with possible iron-oxide alteration
igneous
Pumice
Pumice (volcanic glass foam)
igneous
Basalt River Stone
Basalt (Aphanitic Mafic Igneous Rock)
igneous
Diorite
Diorite (Intermediate intrusive igneous rock)
igneous
Diorite
Diorite (Intermediate intrusive igneous rock)
igneous
Diorite (Polished Tumble)
Diorite (Intermediate intrusive igneous rock)
Igneous
Diorite (Salt and Pepper Rock)
Diorite
igneous
Chalcedony (Grey/White Agate)
Silicon Dioxide (SiO₂)
mineral
Weathered iron-rich rock, possibly basalt or ironstone
Uncertain; likely weathered basalt (plagioclase–pyroxene) or hematite/goethite-bearing ironstone
igneous
Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Polished granite sphere
Granite, chiefly quartz, alkali feldspar, and plagioclase with dark biotite/amphibole minerals
igneous
Granite Water-Worn Pebble
Phaneritic Felsic Igneous Rock (Granite)
igneous
Pebble (Likely Basalt or Siltstone)
Clastic sedimentary rock or mafic volcanic rock
Igneous or Sedimentary
Diorite (or salt-and-pepper granite pebble)
Phaneritic Igneous Rock (Intermediate Composition)
igneous