Obsidian
Obsidian (Volcanic Glass, SiO2)
Category
Browse mineral like (natural glass) specimens identified by the Rock Identifier community.
Obsidian
Obsidian (Volcanic Glass, SiO2)
Faceted yellow-brown gemstone earring
Likely citrine (quartz, SiO₂), though treated quartz or synthetic glass cannot be confirmed from the image
Aquamarine
Beryl (Be3Al2Si6O18 with iron impurities)
Gold-bearing Quartz
Native Gold (Au) in Quartz (SiO2) matrix
Mixed mineral and rock collection
Predominantly quartz varieties, including amethyst, plus likely calcite, feldspar, mica, and miscellaneous polished stones
Quartz pebble
Silicon dioxide (SiO2)
Sandstone (Banded)
Arenite
Epidosite (Epidote-Quartz rock)
Epidote-rich hydrothermal rock
Quartz
Silicon Dioxide (SiO2)
Shale (Ferruginous)
Laminated Mudrock (Siliciclastic Sedimentary Rock)
Weathered quartz-rich rock, possibly chert or quartzite fragment
Indeterminate; likely microcrystalline quartz (SiO₂), possibly with iron-oxide staining
Gravel and Sand Aggregate
Unconsolidated Clastic Sediment
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide, SiO2)
Diamond
C
Quartz (Milky/Smoky variety on matrix)
Silicon Dioxide (SiO2)
Chert (Hag Stone / Hole Stone)
Chert (Cryptocrystalline variety of Quartz, SiO2)
Citrine
Silicon Dioxide (Quartz variety), SiO2
Red Jasper (Beach Pebble)
Jasper (Cryptocrystalline Quartz, SiO2)
Snowflake Obsidian
Vitreous volcanic silicate (SiO2 with Cristobalite inclusions)
Milky Quartz Pebble with Matrix
Quartz (SiO2)
Golden Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz (Milky/Common)
Silicon Dioxide (SiO2)
Red Jasper
Jasper (Silicate Mineral), SiO2 with Fe2O3 inclusions
Amber
Succinite (fossilized tree resin)
Milky Quartz
Silicon Dioxide (SiO2)
Natural Gold Nugget
Native Gold (Au)
Smoky Quartz
Silicon dioxide (SiO2)
Tumbled Mixed Gemstones and Rocks
Various mineral species including quartz (SiO2) and silicate minerals
Diamond (or Clear Quartz / Cubic Zirconia)
Carbon (C) or Silicon Dioxide (SiO2) / Cubic Zirconia (ZrO2)
Witch Stone (Hag Stone)
Perforated Sedimentary Rock (Typically Sandstone or Limestone)
Quartz with Iron Oxide Inclusions
Silicon Dioxide (SiO2)
Magnetite / Ironstone Pebble
Magnetite (Fe3O4)
Sandstone Pebble
Arenite (SiO2 complex)
Ruby
Corundum (Al2O3:Cr)
Brecciated Red Jasper
Microcrystalline Quartz (Chalcedony), SiO2
Pearl
Calcium Carbonate (primarily Aragonite and Calcite), CaCO3
Opal
Hydrated amorphous silica (SiO2·nH2O)
Lepidolite
K(Li,Al)3(Al,Si,4)10(O,F,OH)2
Citrine
Silicon Dioxide (Quartz variety), SiO2
Quartz with Mica/Host Rock
Silicon Dioxide (SiO2) with Phyllosilicates