Tiger’s eye
Quartz variety, primarily silicon dioxide (SiO₂); fibrous quartz pseudomorph after crocidolite asbestos
gemstone
Category
Mineral And Metamorphic Rock
Browse mineral and metamorphic rock specimens identified by the Rock Identifier community.
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Quartzite Pebble
Metamorphic rock predominantly composed of Quartz (SiO2)
metamorphic
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Garnet (Almandine or Spessartine likely)
Garnet Group Minerals (e.g., Almandine Fe3Al2(SiO4)3, Pyrope Mg3Al2(SiO4)3, Spessartine Mn3Al2(SiO4)3)
Mineral
Quartz Vein in Gneiss or Schist
Silicon dioxide (SiO2) within metamorphic host rock
metamorphic
Fuchsite (Chrome Mica)
K(Al,Cr)2(AlSi3O10)(OH)2
mineral
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Serpentine Pebble
Serpentine ((Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al)2O5(OH)4)
metamorphic
Sapphire
Corundum (Al₂O₃) with trace elements causing color variations.
Mineral
Agate Geode
Silicon Dioxide (SiO2) - Chalcedony variety
sedimentary
Unakite
Epidotized Granite
metamorphic
Jasper
Silicon dioxide (SiO2)
sedimentary
Sandstone with Iron Banding
Arenite with Hematite or Limonite staining (SiO2 with Fe2O3)
sedimentary
Granite
Phaneritic plutonic rock (primarily Quartz, Feldspar, and Mica)
igneous
Granite
Phaneritic Igneous Rock (Granite)
igneous
Rounded basalt cobble (probable)
Basalt; fine-grained mafic volcanic rock, chiefly plagioclase and pyroxene
igneous
Quartzite with Milky Quartz Vein
Metamorphosed Quartz-rich Rock (SiO2)
metamorphic
Serpentine
Antigorite, Lizardite, and Chrysotile (Mg3Si2O5(OH)4)
metamorphic
Serpentinite
Serpentinite (composed primarily of serpentine-group minerals like antigorite, chrysotile, and lizardite; chemical formula varies but generally Mg3Si2O5(OH)4)
Metamorphic Rock
Amazonite
KAlSi3O8 (Potassium Aluminum Silicate) - a variety of Microcline Feldspar
mineral
Serpentine
Serpentine Group Minerals (e.g., Antigorite, Chrysotile, Lizardite)
Mineral, often found as a rock
Mixed Tumbled Gemstones and River Rocks
Mixed Decorative Stones (predominantly Silicon Dioxide - SiO2 variants)
Mixed (Igneous, Sedimentary, Metamorphic, and Minerals)
Polished blue-green stone, likely serpentine or chrysocolla-bearing rock
Serpentine-group minerals, chiefly Mg₃Si₂O₅(OH)₄; exact identification requires testing
metamorphic
Serpentine
Antigorite, Lizardite, or Chrysotile; Mg3Si2O5(OH)4
metamorphic
Green Aventurine
Silicon Dioxide with Fuchsite (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)
metamorphic
Gray Quartzite with Quartz Veining
Metamorphosed Quartz-rich Sandstone
metamorphic
Quartz (Float/Abraded)
Quartz (SiO₂)
Mineral
Quartzite
Metamorphic Quartz Sandstone
metamorphic
Quartz crystal (likely milky quartz)
Quartz, silicon dioxide (SiO₂)
mineral
Weathered granitic rock
Granite or granodiorite, likely quartz–feldspar–mica aggregate
igneous
Blue Topaz
Aluminum silicate fluoride hydroxide (Al2SiO4(F,OH)2)
gemstone
Lepidolite
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)
mineral
Glauconitic Sandstone (Greensand)
Glauconitic Sandstone (Iron-potassium phyllosilicate mineral: (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)
sedimentary
Kidney Stone (Medical Specimen)
Calcium oxalate monohydrate (Whewellite) / CaC2O4·H2O
Mineral (Biogenic)
River Pebble (Quartz-rich)
Silicon Dioxide (SiO2) with impurities
sedimentary
Quartzite
Metamorphic Rock (composed primarily of Quartz, SiO2)
metamorphic
Quartz Geode/Cluster
Quartz (SiO2)
mineral
Unakite
Unakite (altered granitic rock)
metamorphic
Granitic Gneiss
Gneiss (Granite-derived)
metamorphic
Quartz with Mica Schist (Pegmatite Specimen)
SiO2 (Silicon Dioxide) and Phyllosilicates (Biotite/Muscovite)
Igneous/Metamorphic Hybrid
River Pebble (Granite/Gneiss)
Granitic Pebble (Quartz, Feldspar, Mica composition)
igneous
Quartzite
Metamorphic Quartz (SiO2)
metamorphic