Possible tektite or volcanic glass specimen
Natural silica glass; composition commonly near SiO₂, but exact identification requires chemical testing
mineral
Category
Mineral (Man Made Glass, Not Natural)
Browse mineral (man made glass, not natural) specimens identified by the Rock Identifier community.
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Sandstone
Arenite (siliciclastic sedimentary rock composed mostly of quartz)
sedimentary
Tumbled citrine quartz (likely heat-treated amethyst)
Quartz, SiO₂; crystalline variety citrine
mineral
Citrine
Silicon Dioxide (Quartz variety), SiO2
mineral
Granite, possibly granodiorite
Coarse-grained felsic plutonic rock; chiefly quartz (SiO₂), potassium feldspar and plagioclase feldspar, with biotite and/or hornblende
igneous
Dyed Pink Agate Slice
Silicon Dioxide (SiO2) - Chalcedony variety Agate
mineral
Conglomerate
Conglomerate
sedimentary
Magnetite (Iron Ore)
Magnetite (Fe3O4)
mineral
Riverstone (Sandstone Pebble)
Arenite (SiO2 with various lithic fragments)
sedimentary
Yellow tumbled/rough chalcedony, possibly citrine or dyed agate
Chalcedony (microcrystalline SiO₂), with yellow coloration likely from iron oxides; exact identification is uncertain from the photograph
mineral
Sandstone Pebble
Quartz Sandstone
sedimentary
Sandstone / Chert Pebble
Silicon Dioxide / Sedimentary Rock (SiO2)
sedimentary
Witch Stone (Hag Stone)
Perforated Sedimentary Rock (Typically Sandstone or Limestone)
sedimentary
Sand Tiger Shark Tooth (Fossil)
Carcharias taurus (fossilized dentin/enameloid)
fossil
Brecciated jasper (likely red-and-cream jasper)
Jasper, an opaque microcrystalline variety of quartz; primarily cryptocrystalline SiO₂ with iron-oxide staining and possible chalcedony/quartz veining
gemstone
Diamond
Carbon (C)
mineral
Granite
Granite (Felsic Plutonic Rock)
igneous
Chrysocolla in Malachite
Cu2CO3(OH)2 (Malachite) / Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O (Chrysocolla)
mineral
Red Jasper with Quartz Veining
Jasper (Silicon Dioxide, SiO2)
sedimentary
Magnetite / Ironstone Pebble
Magnetite (Fe3O4)
mineral
Diamond (or Clear Quartz / Cubic Zirconia)
Carbon (C) or Silicon Dioxide (SiO2) / Cubic Zirconia (ZrO2)
gemstone
Brecciated Red Jasper
Microcrystalline Quartz (Chalcedony), SiO2
sedimentary
Pearl
Calcium Carbonate (primarily Aragonite and Calcite), CaCO3
mineral
Weathered pink granite fragment
Granite, chiefly quartz, potassium feldspar, and plagioclase feldspar with minor mica
igneous
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Mixed Mineral Collection (with Titanium Aura Quartz)
Silicon Dioxide (SiO2) with metallic coatings and various silicates
mineral
Riverstone Quartzite (Water-worn Siltstone/Quartzite)
Metamorphosed Quartz-rich Arenite (SiO2)
metamorphic
Flint / Chert
Silicon Dioxide (SiO2)
sedimentary
Sandstone
Arenite (typically SiO2 based)
sedimentary
Quartzite Pebble
Quartzite (primarily SiO2)
metamorphic
Herkimer Diamond
Quartz (Silicon Dioxide, SiO2)
mineral
Green Aventurine
Quartzite with Fuchsite inclusions (SiO2)
metamorphic
Slag (Industrial Glass)
Artificial Vitreous Silicate
mineraloid (anthropogenic)
Pumice
Pumice (Felsic vesicular volcanic glass)
igneous
Blue Howlite (Dyed)
Dyed Howlite (Calcium Borosilicate Hydroxide, Ca2B5SiO9(OH)5)
mineral
Fluorite (specifically Rainbow Fluorite or Purple Fluorite)
Calcium Fluoride (CaF2)
mineral
Magnetite (Octahedral Crystal)
Magnetite (Fe3O4)
mineral
Magnetite
Magnetite (Fe3O4)
mineral
Pink Granite (Alkali-feldspar Granite)
Felsic intrusive igneous rock (composition: KAlSi3O8, SiO2, NaAlSi3O8)
igneous
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Pyrite
Iron Disulfide (FeS2)
mineral