Quartzite
Quartzite (SiO2)
metamorphic
Category
Industrial Byproduct (Often Mistaken For Obsidian Or Mineral)
Browse industrial byproduct (often mistaken for obsidian or mineral) specimens identified by the Rock Identifier community.
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Serpentine
Serpentinite (group of minerals based on (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4)
metamorphic
Quartzite (Iron-stained River Rock)
Metamorphic Rock consisting primarily of Quartz (SiO2)
metamorphic
Silver (Sterling Silver Jewelry)
Argentum (Ag) mixed with Copper (Cu)
mineral
Quartzite
Quartzite (primarily SiO2)
metamorphic
Quartzite
Quartzite (primarily SiO2)
metamorphic
Blue Quartzite (Blue Aventurine / Dumortierite Quartz)
Quartzite with inclusions (SiO2 with AlAl4BSi3O18)
metamorphic
Pegmatite
Igneous Pegmatite
igneous
Polished serpentine (likely bowenite)
Serpentine-group minerals, chiefly antigorite, Mg₃Si₂O₅(OH)₄; may contain magnetite and carbonate veins
metamorphic
Mahogany Obsidian
Volcanic glass (high silica) with inclusions of Magnetite or Hematite
igneous
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
mineral
Tumbled snowflake obsidian
Obsidian (volcanic glass), SiO₂, with cristobalite spherulites
igneous
Opalite
Synthetic Opalized Glass
gemstone
Polished black stone egg, probably black obsidian
Obsidian, a natural volcanic glass; composition primarily silica-rich glass (approximately SiO₂), with variable iron and other trace elements
gemstone
Snowflake Obsidian
Spherulitic Obsidian (SiO2 + impurities)
igneous
Quartz with Mica (Muscovite/Biotite)
Silicon Dioxide (SiO2) with Phyllosilicate inclusions
mineral
Black Onyx
Silicon Dioxide (SiO2) with carbon impurities
mineral
Diorite
Intermediate Phaneritic Igneous Rock (Diorite)
igneous
Obsidian
Volcanic glass (no mineral formula due to amorphous structure, mostly SiO2)
igneous
Polished black pebble, likely basalt
Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase feldspar and pyroxene, commonly with olivine
igneous
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
mineral
Snowflake Obsidian
Volcanic Glass with Cristobalite Inclusions
igneous
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Kambaba Jasper
Stromatolite
sedimentary/fossil
Chert (Iron-stained)
Microcrystalline Silica (SiO2)
sedimentary
Snowflake Obsidian
Volcanic glass with Phenocrysts (SiO2)
igneous
Black Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
igneous
Obsidian (black volcanic glass)
Obsidian; predominantly rhyolitic volcanic glass, mainly SiO₂ with minor feldspar, quartz, and iron oxides
igneous
Mixed Tumbled Gemstones (Agate, Aventurine, Pyrite, etc.)
Multiple (principally Silicon Dioxide SiO2 and Iron Disulfide FeS2)
mineral
Green Aventurine
Quartz variety (SiO2 with inclusions)
mineral
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
mineral
Concrete fragment with Aggregate
Anthropogenic Concrete with Calcarious and Siliceous Aggregate
sedimentary (anthropogenic/man-made)
Mahogany Obsidian
Obsidian (volcanic glass with Hematite/Magnetite inclusions)
igneous
Snowflake Obsidian
Obsidian with Spherulitic Cristobalite (SiO2)
igneous
Sodalite
Sodalite - Na8(Al6Si6O24)Cl2
mineral
Snowflake Obsidian
Spherulitic Obsidian (primarily SiO2)
igneous
Black Obsidian
Obsidian (Volcanic Glass, SiO2 + impurity)
igneous
Snowflake Obsidian
Vitreous volcanic rock with Cristobalite inclusions (mostly SiO2)
igneous
Green Quartzite (Aventurine type)
Quartzite (principally Quartz, SiO2) with inclusions of Fuchsite
metamorphic
Serpentine
Antigorite, Lizardite, and Chrysotile (Mg3Si2O5(OH)4)
metamorphic
Ferruginous Quartz (Iron-stained Quartz)
Silicon Dioxide (SiO2) with iron oxide inclusions/staining (Limonite/Hematite)
Mineral
Satin Spar (Gypsum)
Calcium Sulfate Dihydrate (CaSO4·2H2O)
mineral