Tektite
Natural impact glass
meteorite
Category
Mineral (Man Made Composite)
Browse mineral (man made composite) specimens identified by the Rock Identifier community.
Learn about Mineral (Man Made Composite) in the encyclopedia
View all →
Yellow chalcedony (likely agate) cabochons
Microcrystalline quartz, SiO₂; chalcedony variety, possibly naturally colored or dyed
gemstone
Riverstone (Sandstone Pebble)
Arenite (SiO2 with various lithic fragments)
sedimentary
Granite
Intrusive Felsic Igneous Rock (primarily Quartz and Feldspar)
igneous
Sandstone (Pebble)
Sandstone (SiO2 with matrix/cement)
sedimentary
Chalcedony (Agate/Chert variety)
Silicon Dioxide (SiO2)
mineral
Tumbled hematite
Hematite (Fe₂O₃), likely specular or massive hematite
mineral
Polished blue stone, likely sodalite or dyed agate
Sodalite: Na₈(Al₆Si₆O₂₄)Cl₂; exact identification requires testing
mineral
Tumbled amethyst quartz
Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation
gemstone
Faceted brown gemstone pendant, likely smoky quartz or champagne topaz
Probably quartz (SiO₂), smoky variety; alternatively topaz (Al₂SiO₄(F,OH)₂)
gemstone
Chert
Silicon dioxide (SiO2)
Sedimentary
Bauxite
Bauxite (Al(OH)3, AlO(OH))
sedimentary
Engraved purple stone cabochon, possibly amethyst
Unconfirmed; if amethyst, quartz (SiO₂)
gemstone
Sandstone
Sedimentary Rock (Quartz Sandstone)
sedimentary
Kidney Stone
Calcium oxalate, uric acid, struvite, or cystine
mineral
Obsidian
Volcanic Glass (SiO2)
igneous
Aragonite Star Cluster
Aragonite (Calcium Carbonate, CaCO3)
mineral
Sunstone (Aventurine Feldspar)
(Ca,Na)((Al,Si)2Si2O8) with inclusions of Cu or Fe2O3
mineral
Diamond
Carbon (C)
mineral
Diamond
Diamond (pure Carbon, C)
mineral
Rough Diamond
Pure Carbon (C)
mineral
Sunstone
(Ca,Na)((Al,Si)2Si2O8) - Plagioclase Feldspar
mineral
Pearl
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
mineral
Polished orbicular jasper
Jasper, microcrystalline quartz (SiO₂), with iron oxides and other inclusions
mineral
Red Sandstone
Arenite (Fe2O3 enriched)
sedimentary
Rounded pink granite cobble
Granite, chiefly quartz–alkali feldspar–plagioclase–biotite
igneous
Greenstone
Metamorphic mafic rock (chlorite-actinolite-epidote schist)
metamorphic
Blue Chalcedony
Silicon Dioxide (SiO2) - Microcrystalline Quartz
mineral
Granite
Phaneritic Felsic Igneous Rock
igneous
Chert (Chalcedony/Agate variety)
Silicon Dioxide (SiO2)
sedimentary
Tumbled chalcedony or quartz pebble
Microcrystalline quartz, SiO₂ (likely chalcedony); exact identification is uncertain from the image
mineral
Botryoidal chalcedony with iron-oxide staining
Microcrystalline quartz (SiO₂), likely iron-oxide-bearing chalcedony
mineral
Blue Slag Glass
Ferro-silicate glass (Slag)
igneous (man-made/industrial)
Gabbro
Gabbro
igneous
Sandstone (with potential Arkose/Lithic characteristics)
Arenite (Sedimentary rock composed of sand-sized grains)
sedimentary
Carved serpentine pendant
Serpentine-group minerals, commonly antigorite/lizardite (Mg₃Si₂O₅(OH)₄), possibly mixed with chlorite or other inclusions
mineral
Amber jewelry (possibly amber-colored glass or resin)
Amber — fossilized plant resin, chiefly composed of polymerized terpenoids; the pictured material cannot be confirmed from the image
gemstone
Nephrite Jade
Nephrite
Mineral/Rock
Granite
Plutonic Igneous Rock (composed typically of SiO2, Al2O3, K2O, Na2O, CaO)
igneous
Native silver fragment (probable)
Silver, Ag; possibly silver-bearing sulfide or plated metal
mineral
Synthetic Marbled Aggregate (Footwear Component)
Ethylene-vinyl acetate (Croslite™)
not a rock (man-made polymer)
Sandstone
Arenite (variable SiO2 composition)
sedimentary