Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Category
Mixed (Predominantly Sedimentary And Igneous)
Browse mixed (predominantly sedimentary and igneous) specimens identified by the Rock Identifier community.
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Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Obsidian (specifically Rainbow or Silver Sheen Obsidian)
Volcanic Glass (predominantly SiO2)
Igneous
Black Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Quartzite (Rounded Pebble)
Quartzite (predominantly SiO2)
metamorphic
Pumice
Vesicular volcanic glass (Amorphous silica mixed with various oxides)
igneous
Scoria (Lava Rock)
Scoria (extrusive volcanic rock)
igneous
Turquoise
Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)
mineral
Mixed Chalcedony and Jasper Bracelet (possibly 'Ocean Jasper' or similar banded variety for brown beads, and blue/grey Chalcedony for the translucent beads)
Chalcedony (SiO2), Jasper (SiO2 with impurities)
Mineral (specifically a cryptocrystalline variety of Quartz)
Red Jasper (in Quartz/Chalcedony)
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Costume Jewelry Gemstones (Emerald-imitation and semi-precious beads)
BeCuAl6Si6O18 (Beryl structure), frequently simulated by glass or synthetic spinel
mineral
Sandstone
Sedimentary Rock (Quartz Sandstone)
sedimentary
Citrine Quartz
Silicon Dioxide (SiO2) with iron impurities
mineral
Labradorite
Labradorite ((Ca, Na)(Al, Si)4O8)
mineral
Concrete
Anthropogenic Sedimentary Conglomerate (Cement mixture: typically Ca2SiO4, Ca3SiO5, Ca3Al2O6)
sedimentary (artificial)
Red Jasper (possibly Red Coral or dyed Howlite)
Silicon Dioxide (SiO2) with Iron Oxide inclusions
sedimentary
Granite
Granite
Igneous
Hypersthene
Hypersthene ((Mg,Fe)SiO3)
mineral
Ironstone Pebble
Ferruginous sedimentary rock (Fe2O3 / FeO(OH) mixed with SiO2)
sedimentary
Mixed rock fragments, likely granite and weathered metamorphic rock
Granite (quartz–feldspar–mica aggregate) with probable schist/gneiss fragments
igneous and metamorphic
White Topaz
Aluminum Silicate Fluoride Hydroxide; Al2SiO4(F,OH)2
mineral
Flint
Microcrystalline Quartz (SiO2)
sedimentary
Citrine
Silicon Dioxide (SiO2) with iron impurities
mineral
Granite
Granite
igneous
K-Feldspar Granite Fragment
Granite (Alkali Feldspar-rich)
igneous
Botryoidal hematite (iron-oxide specimen)
Hematite, Fe₂O₃; possibly mixed with goethite/limonite
mineral
Amethyst (Pale/Light Variety)
Quartz (Silicon Dioxide) with Iron impurities - SiO2
mineral
Sodalite
Sodalite - Sodium Aluminum Silicate Chloride (Na8(Al6Si6O24)Cl2)
mineral
Granite Pebble
Intrusive Igneous Rock
igneous
Unidentified Rock Fragment
Unknown
Rock
Kambaba Jasper
Stromatolite (Fossilized Algae)
sedimentary
Quartz-rich granite or granitic pegmatite
Granite; predominantly quartz (SiO₂), feldspar, and possibly mica
igneous
Likely rose quartz-bearing pegmatite
Quartz (SiO₂), probably with feldspar and iron-oxide staining
mineral
Gold Flakes
Native Gold (Au)
mineral
Granite
Granite (composed of quartz, potassium feldspar, plagioclase, and mica/biotite)
igneous
Granite
Intrusive Igneous Rock
igneous
Jasper, Agate, Quartz Mix (Polished Beads)
SiO₂ (Silicon Dioxide) for Quartz. Jasper and Agate are cryptocrystalline varieties of Quartz.
Mineral/Semiprecious Gemstone (variety of Quartz)
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone
Clastic sedimentary rock (Quartz arenite or Arkose)
sedimentary
Sandstone
Clastic Sedimentary Rock
sedimentary
Quartz (River Pebble)
Quartz (Silicon Dioxide, SiO2)
mineral