Chert Arrowhead
Cryptocrystalline Quartz (SiO2)
Category
Browse anthropogenic (man made material processed by nature) specimens identified by the Rock Identifier community.
Chert Arrowhead
Cryptocrystalline Quartz (SiO2)
Silicon Carbide
Silicon Carbide (Moissanite / Carborundum), SiC
Beaded gemstone bracelet
Indeterminate; likely small polished mineral beads, possibly turquoise or dyed stone, with metal and glass components
Opalite-style pendant (likely synthetic glass, not natural opal)
Opalescent glass; commonly sold as “opalite” (not a recognized mineral species)
Sandstone Concretion
Siliciclastic Concretion
Sandstone Concretion
Clastic Sedimentary Concretion (SiO2 with Iron Oxide)
Possible sea glass (naturally frosted glass), not a confirmed geological specimen
Man-made silicate glass; composition varies, commonly soda-lime glass
Conglomerate
Clastic Sedimentary Rock (Conglomerate)
Sandstone (with Liesegang rings or joints)
Clastic Sedimentary Rock (primarily Quartz with Iron Oxide cement)
Chert (Arrowhead)
Chert (SiO2)
Sea Glass (Kelly Green)
Amorphous Silica (Silicon Dioxide with Iron/Chromium additives)
Libyan Desert Glass
Tektite (high-silica impact glass), SiO2
Graphite
Graphite (Carbon, C)
Green sea glass (likely)
Anthropogenic glass, not a mineral; composition commonly soda–lime silicate glass
Bismuth crystal
Bismuth (Bi), synthetic laboratory-grown crystal
Dyed Quartz Geode
Silicon Dioxide (SiO2) with artificial pigment
Coquina
Biogenic Limestone (Coquina)
Polished black stone, likely black obsidian
Volcanic glass; predominantly rhyolitic silica glass (SiO₂-rich)
Rock crystal (clear quartz), possibly cloudy quartz
Quartz, silicon dioxide (SiO₂)
Mixed gemstone bead strand, likely including agate, quartz, turquoise, and sandstone beads
Varied silicate and copper-mineral materials; exact bead identities cannot be confirmed visually
Obsidian
Volcanic Glass
White quartz pebble or chip
Quartz (silicon dioxide, SiO₂), possibly milky quartz
Unidentified translucent crystal/mineral fragment
Likely quartz (SiO₂), but visual identification is uncertain
Tumbled white chalcedony (likely milky quartz)
Chalcedony, microcrystalline quartz (SiO₂)
Green Aventurine
Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2
Green Quartz / Chrysoprase / Sea Glass
Silicon Dioxide (SiO2)
Clear quartz crystal
Quartz (silicon dioxide, SiO₂)
Chert Arrowhead (Projectile Point)
Chert (Cryptocrystalline Quartz, SiO2)
Nephrite Jade
Nephrite
Goldstone (with Tiger's Eye and Quartz)
Aventurine glass (Synthetic SiO2 with Cu inclusions)
White pebbles (rock material not identifiable from the image)
Undetermined; the smooth, pale pieces could be quartz, quartzite, or another light-colored rock
Opalite
Synthetic opalescent glass
Iron Slag
Anthropogenic Vitreous Silicate (Byproduct of Smelting)
Blue glassy mineral specimen, possibly dyed or synthetic
Uncertain; possible blue fluorite (CaF₂), dyed chalcedony, or man-made glass
Concretion
Sedimentary Concretion (Ironstone / Calcite Concretion)
Sandstone Concretion
Sedimentary Clastic Rock (Silicate-rich)
Sandstone Concretion
Clastic Sedimentary Concretion (typically Quartz/Silica with Iron Oxide)
Libyan Desert Glass
Libyan Desert Glass (SiO2 with trace elements)
Weathered iron-rich concretion or ironstone nodule
Goethite–hematite limonite concretion (FeO(OH), Fe₂O₃, and hydrated iron oxides)
Flint
Silicon Dioxide (SiO2) - Chert variety
Cherry Quartz
SiO2 (Silicon Dioxide with iron-rich inclusions/dye)
Hematite Beads
Hematite (Fe2O3)