Granite Pebble (Salt and Pepper Granite)
Felsic Intrusive Igneous Rock (Granite)
igneous
Category
Basalt
Browse basalt specimens identified by the Rock Identifier community.
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Porphyritic Basalt (with Quartz or Calcite inclusion)
Porphyritic Basalt (Matrix: SiO2/MgO/FeO, Phenocryst: likely Quartz or Calcite)
igneous
Vesicular Basalt with Oxidation
Scoriaceous Olivine Basalt (Mafic volcanic rock)
igneous
Industrial Slag
Anthropogenic Vitreous Slag
igneous
Granite
Phaneritic Plutonic Felsic Rock (Granite)
igneous
Plagioclase Feldspar (specifically Albite/Oligoclase)
(Na,Ca)(Si,Al)4O8
mineral
Peridot
Olivine (Magnesium Iron Silicate), (Mg, Fe)2SiO4
mineral
Olivine (Peridotite)
(Mg,Fe)2SiO4 (Magnesium Iron Silicate)
igneous
Olivine (Peridotite/Dunite)
Olivine (Mg,Fe)2SiO4 within Peridotite
igneous
Basalt or Siltstone Pebbles
Mafic volcanic rock (Basalt) or Indurated Siltstone
igneous or sedimentary
Vesicular Basalt (Scoria)
Mafic extrusive volcanic rock (predominantly Plagioclase feldspar and Pyroxene)
igneous
Porphyritic Basalt (with Augite Crystals)
Porphyritic Mafic Volcanic Rock (Fe-Mg Silicates)
igneous
Basalt with Desert Varnish
Mafic Volcanic Rock (Fe/Mg rich Silicate)
igneous
Vesicular Basalt (Scoria)
Extrusive Mafic Volcanic Rock (FeO-SiO2-MgO)
Igneous
Basalt with Epidote (Greenstone)
Amygdaloidal Basalt (Ca2(Al, Fe)3(SiO4)3(OH) inclusions)
igneous
Amygdaloidal Basalt with Epidote
Vesicular Basalt with secondary Epidote/Quartz mineral infill
igneous
Scoria (Vesicular Basalt)
Scoria (Vesicular Igneous Rock)
igneous
Porphyritic Basalt (or Porphyry)
Porphyritic Andesite/Basalt (primarily Plagioclase feldspar and Pyroxene)
igneous
Jasper in Basalt Matrix
Silicon Dioxide (SiO2) with impurities; Chalcedony
sedimentary (secondary mineral) within igneous
Porphyritic Andesite or Basalt
Porphyritic Intermediate/Mafic Igneous Rock
igneous
Scoria (Vesicular Basalt)
Scoria (Extrusive Igneous Rock)
igneous
Scoria (Vesicular Basalt)
Scoria (Extrusive Mafic Igneous Rock)
igneous
Olivine in Basalt matrix
Peridotite (Mg, Fe)2SiO4
igneous
Basalt with Quartz Vein
Basalt (extrusive igneous rock) with Quartz (SiO2) inclusion
igneous
Banded Chalcedony (Agate) in Basalt Matrix
Cryptocrystalline Quartz (SiO2) in Mafic Igneous Rock
sedimentary/igneous
Amethyst and Citrine (Ametrine Mix)
Silicon Dioxide (SiO2) with Fe3+ impurities
mineral
Greenstone
Greenschist (containing chlorite, epidote, and actinolite)
metamorphic
Banded Agate Geode
Silicon Dioxide (SiO2)
mineral
Carnelian
Carnelian (Silicon Dioxide - SiO2)
mineral
Magnetite / Iron Ore
Magnetite (Fe3O4)
mineral
Magnetite (potentially as a Lodestone or within Ironstone)
Magnetite (Fe3O4)
mineral
Banded Agate (specifically Moss Agate or Plume Agate variety)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Andesite
Andesite (Intermediate Extrusive Volcanic Rock)
igneous
Peridot (Olivine)
(Mg,Fe)2SiO4 (Magnesium Iron Silicate)
mineral
Scoria
Vesicular Basalt / Scoria (Mafic silicate rock)
Igneous
Prehnite
Prehnite - Ca2Al(AlSi3O10)(OH)2
mineral
Scoria (Lava Rock)
Aphanitic vesicular mafic igneous rock
igneous
Ruby (Pink to Red Corundum)
Al2O3 (Corundum with Chromium impurities)
mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Blue Lace Agate (Banded Chalcedony)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
mineral
Amethyst
Amethyst (Silicon Dioxide, SiO2 with Iron impurities)
mineral
Amethyst
Silicon Dioxide (SiO2) with Fe3+ impurities
mineral