Vesicular Basalt
Mafic Igneous Rock
igneous
Category
Sedimentary (Volcanic)
Browse sedimentary (volcanic) specimens identified by the Rock Identifier community.
Agate (specifically Lake Superior Agate style or Banded Chalcedony)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Amethyst
Silicon Dioxide with Iron impurities (SiO2 + Fe3+)
mineral
Gossan (Iron Hat)
Limonitic Gossan (Fe-oxide/hydroxide complex)
igneous
Basalt
Aphanitic Mafic Igneous Rock
igneous
Basalt
Basalt (comprising Plagioclase feldspar, Pyroxene, and Olivine)
igneous
Diabase (Greenstone Pebble)
Diabase or Dolerite
igneous
Iron-stained Milky Quartz
Silicon Dioxide (SiO2) with iron oxide inclusions
mineral
Vesicular Basalt (Aqueous Tumbled)
Scoriaceous Basalt
igneous
Obsidian with Spherulitic Devitrification (Snowflake Obsidian/Mahogany related)
Volcanic Glass (70% or more SiO2)
igneous
Diamond
Diamond (C)
Mineral
Basalt with Quartz/Feldspar Vein
Amygdaloidal Basalt with Plutonic intrusion (SiO2/KAlSi3O8)
igneous
Diamond
Diamond (C)
Mineral
Iron Slag
Vitreous glassy waste (Fe-Si-Al-Ca compounds)
Mineral byproduct (anthropogenic / techno-fossil)
Slag (Industrial Glass/Metal)
Ferrous slag or Glassy silicate byproduct
Antropogenic rock (Man-made)
Basalt with Quartz Vein
Basalt (SiO2 vein inclusion)
igneous
Peridot
Olivine (specifically, the gem-quality variety forsterite, (Mg,Fe)2SiO4)
Mineral
Sunstone
Plagioclase Feldspar (specifically Oligoclase variety containing hematite or goethite inclusions)", composition: (Ca,Na)(Al,Si)2Si2O8
Mineral
Carnelian
Carnelian (Silicon Dioxide - SiO2)
mineral
Cullet Glass (Industrial Slag Glass)
Amorphous Silica (SiO2) with metallic oxide impurities
Man-made byproduct (often mistaken for Obsidian or Emerald)
Tektite (Indochinite)
Tektite (Amorphous silica-rich impact glass)
igneous
Slag
Glassy silicate byproduct (anthropogenic material)
industrial byproduct
Slag Glass
Amorphous Silica / Glass Slag
industrial byproduct (anthropogenic rock-like material)
Slag Glass (Cullet)
Amorphous Silicon Dioxide (SiO2) with metal oxide colorants
Anthropogenic (Man-made)
Orthoclase Feldspar (Twinning Specimen)
Orthoclase (KAlSi3O8)
mineral
Amethyst
Quartz (SiO2) variety
Mineral
Quartz on Sandstone
Silicon Dioxide (SiO2) in Lithic Sandstone
sedimentary
Sandstone
Arenite (SiO2 based)
sedimentary
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Sandstone
Arenite (SiO2 principal component)
sedimentary
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone (likely Arkose or Quartz Sandstone)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Ocean Jasper (Orbicular Jasper)
Silicon Dioxide (SiO2) with iron and magnesium inclusions
mineral
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
mineral
Tiffany Stone
Bertrandite (with Fluorite, Opal, and Chalcedony), Be4Si2O7(OH)2
mineral
Basalt
Basalt
igneous
Banded Agate (specifically Botswana Agate appearance)
Silicon Dioxide (SiO2)
mineral
Basalt
Aphanitic mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
igneous
Vesicular Basalt (Amygdaloidal)
Vesicular Basalt (Fe-Mg rich extrusive volcanic rock)
igneous
Obsidian
Obsidian (principally SiO2)
igneous
Diorite
Diorite (Intermediate intrusive igneous rock)
igneous