Conglomerate
Conglomeratic Sandstone
sedimentary
Category
Mineral Like (Natural Glass)
Browse mineral like (natural glass) specimens identified by the Rock Identifier community.
Learn about Mineral Like (Natural Glass) in the encyclopedia
View all →
Quartz (Crystal Fragment)
Silicon Dioxide (SiO2)
mineral
Magnetite (potentially as a Lodestone or within Ironstone)
Magnetite (Fe3O4)
mineral
Cat's Eye Chrysoberyl
Chrysoberyl (BeAl2O4)
mineral
Obsidian
Obsidian (volcanic glass; primarily SiO2)
igneous
Shale
Shale (composition varies: primarily clay minerals and quartz)
sedimentary
Vesicular Basalt River Rock
Vesicular Basalt
igneous
Pegmatitic pink feldspar–quartz rock
Granitic pegmatite; chiefly microcline/orthoclase feldspar (KAlSi₃O₈), quartz (SiO₂), and minor mica
igneous
Amethyst
Quartz variety; chemical formula: SiO₂ (silicon dioxide) with Fe³⁺ impurities
Mineral
Staurolite (Fairy Cross)
Staurolite (Fe2+2Al9Si4O23(OH))
metamorphic
Obsidian
Volcanic glass
igneous
Howlite
Howlite (Calcium borosilicate hydroxide, Ca2B5SiO9(OH)5)
mineral
White quartz pebble (likely milky quartz)
Quartz, silicon dioxide (SiO₂)
mineral
Sandstone
Arenite (SiO2 based with quartz, feldspar, or lithic fragments)
sedimentary
Coquina or Fossiliferous Conglomerate
Bioclastic Rudstone (variable composition)
sedimentary
Amethyst Quartz
Silicon Dioxide (SiO2) with iron impurities
mineral
Sand (Construction Grade)
Unconsolidated siliciclastic sediment (primarily SiO2)
sedimentary
Tumbled amber
Fossilized tree resin; commonly succinite (organic resin, not a mineral)
fossil
Red jasper pebble
Jasper, microcrystalline quartz (SiO₂) colored mainly by iron oxides
mineral
Smoky Quartz with Hematite Inclusions
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions
mineral
Quartz (River-worn Pebble)
Quartz (SiO2)
Mineral
Polished red banded stone, likely rhodonite
Rhodonite — manganese inosilicate, MnSiO₃; possibly rhodochrosite or dyed quartz
mineral
Grey River Pebble (Greywacke / Basalt)
Stream-rounded silicate rock pebble
sedimentary
Howlite
Howlite (Calcium borosilicate hydroxide, Ca2B5SiO9(OH)5)
mineral
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
igneous
Granite
Phaneritic Igneous Rock (composed primarily of Quartz, Feldspar, and Mica)
igneous
Blue Quartz (Dumortierite Quartz)
SiO2 with inclusions of AlAl6BSi3O18
mineral
Red Sandstone
Arenite (predominantly SiO2 with Fe2O3 staining)
sedimentary
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
mineral
Sandstone
Quartz Arenite (a type of sandstone composed of more than 90% quartz)
Sedimentary Rock
Diamond
Cubic Carbon (C)
mineral
Smoky quartz
Quartz, silicon dioxide (SiO₂), brown to gray variety
mineral
Dyed Agate
SiO2
Mineral
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Tumbled and polished quartz crystal points
Quartz (silicon dioxide, SiO₂), chiefly rock crystal with smoky or included varieties
mineral
Black tourmaline beads (likely schorl)
Schorl, NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄
mineral
Lepidolite
K(Li,Al)3(Si,Al)4O10(F,OH)2
mineral
Dyed Agate Slice
Silicon Dioxide (SiO2) - variety of Chalcedony
mineral
Red cabochon gemstone, likely carnelian
Carnelian: orange-red chalcedony, microcrystalline quartz (SiO₂)
gemstone
Granite
Phaneritic Intrusive Igneous Rock (composed of Quartz, Feldspar, and Mica)
igneous
Dyed Agate
Agate (SiO2)
Mineral
Red jasper pebble
Jasper, microcrystalline quartz (SiO₂) colored mainly by iron oxides
mineral