Magnetite (potentially as a Lodestone or within Ironstone)
Magnetite (Fe3O4)
mineral
Category
Basalt
Browse basalt specimens identified by the Rock Identifier community.
Magnetite / Iron Ore
Magnetite (Fe3O4)
mineral
Banded Agate (specifically Moss Agate or Plume Agate variety)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Porphyritic Basalt (with Augite Crystals)
Porphyritic Mafic Volcanic Rock (Fe-Mg Silicates)
igneous
Scoria
Vesicular Basalt / Scoria (Mafic silicate rock)
Igneous
Vesicular Basalt with Opal or Quartz
Vesicular Basalt (Amorphous SiO2.nH2O if Opal)
igneous
Porphyritic Basalt (Chinese Flower Stone / Chrysanthemum Stone basalt variety)
Porphyritic Basalt containing Plagioclase Feldspar phenocrysts
igneous
River Stone (likely Siltstone or fine-grained Basalt)
Clastic Sedimentary (Siltstone) or Mafic Igneous (Basalt)
sedimentary or igneous
Scoria
Vesicular Basalt / Scoria (Mafic volcanic rock)
igneous
Greenstone Celt (Polished Stone Axe)
Metamorphosed mafic rock (often Basalt or Diabase)
metamorphic
Porphyritic Basalt (Peanut Obsidian/Star Galaxy-style)
Porphyritic Basalt (Silica-rich Volcanic Rock)
igneous
Granite
Phaneritic Plutonic Felsic Rock (Granite)
igneous
Andesite
Andesite (Intermediate Extrusive Volcanic Rock)
igneous
Chalcedony (Yellow Agate/Chert)
Silicon Dioxide (SiO2)
mineral
Carnelian (Red Chalcedony)
Silicon Dioxide (SiO2)
mineral
Druzy Quartz on Chalcedony Matrix
Silicon Dioxide (SiO2)
mineral
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
Vesicular Basalt (Scoria)
Mafic extrusive volcanic rock (predominantly Plagioclase feldspar and Pyroxene)
igneous
Jasper in Basalt Matrix
Silicon Dioxide (SiO2) with impurities; Chalcedony
sedimentary (secondary mineral) within igneous
Scoria (Vesicular Basalt)
Scoria (Vesicular 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
Amethyst
Quartz (Silicon Dioxide with Iron impurities), SiO2
mineral
Rough Sapphire
Corundum (Al2O3)
mineral
Amethyst Geode
Silicon Dioxide with impurities (SiO2)
mineral
Epidote in Matrix (Unakite-related)
Epidosite (Ca2(Al,Fe)3(SiO4)3(OH))
metamorphic
Greenstone (Greenstone River Pebble)
Greenschist (metamorphosed mafic igneous rock)
metamorphic
Greenstone
Metabasalt
metamorphic
Sapphire
Corundum (Al2O3)
mineral
Blue Chalcedony
Cryptocrystalline Quartz (SiO2)
mineral
Amethyst
Amethyst (Silicon Dioxide - SiO2)
mineral
Black Sapphire
Corundum (Al2O3 with inclusions of hematite or ilmenite)
mineral
Chalcedony (Carnelian variety)
Silicon Dioxide (SiO2)
mineral
Sunstone
Orthoclase or Oligoclase Feldspar (Na,Ca)(Al,Si)4O8
mineral
Ruby
Corundum (Al2O3 with Chromium traces)
mineral
Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide
mineral
Chert (Lake Superior Agate variant)
Microcrystalline Quartz (SiO2)
sedimentary
Olivine (Peridot in gem form)
Magnesium Iron Silicate (Mg,Fe)2SiO4
mineral