Fossil shark tooth in sediment
Likely fossilized shark tooth, possibly *Carcharhinus* or *Otodus*; exact identification requires the tooth’s full morphology and locality
fossil
Category
Man Made Material
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Unidentified polished dark gemstone cabochon
Possibly hematite, obsidian, jet, or dark agate; image insufficient for a definitive identification
gemstone
Bauxite
Bauxite (Al(OH)3, AlO(OH))
sedimentary
Natural or Cultured Pearl
Calcium Carbonate (Aragonite and Conchiolin), CaCO3
Mineral (Organic)
Dark gneiss or migmatitic amphibolite
Band ed gneiss; composition likely quartz–feldspar–biotite/amphibole, possibly migmatite
metamorphic
Quartzite
Silica (SiO2) quartzite
metamorphic
Granite
Granite (Felsic Plutonic Rock)
igneous
Sandstone (likely Fossiliferous)
Arenite / Fossiliferous Sandstone (SiO2 composition)
sedimentary
Vesicular basalt (possibly slag-contaminated)
Basalt; chiefly plagioclase and pyroxene, with possible olivine and secondary minerals
igneous
Red-and-brown agate bead bracelet
Agate, a microcrystalline variety of quartz (SiO₂), likely colored chalcedony/carnelian
mineral
Diorite
Diorite
igneous
Diamond
Carbon (C)
gemstone
Banded Sandstone
Arenite with Liesegang banding
sedimentary
Amethyst and aquamarine gemstone bracelet
Amethyst: purple quartz, SiO₂; blue beads likely aquamarine/blue quartz, with possible metallic spacer beads
gemstone
Petrified Wood (Silicified Wood)
Silicified Paleoflora (mainly Quartz, SiO2)
metamorphic
Diorite
Intermediate plutonic igneous rock
igneous
Likely weathered granite or granitic gneiss fragment
Granite; primarily quartz, feldspar, and mica
igneous
Fossilized oyster shell
Bivalvia; likely an oyster (Ostreidae), partly mineralized with calcite
fossil
Gemstone jewelry ensemble
Likely mixed gemstone and glass-bead jewelry; exact stones cannot be determined from the image
gemstone
Chert or silicified sedimentary fragment (tentative)
Microcrystalline quartz (SiO₂), possibly silicified limestone or fossil-bearing chert
sedimentary
Sandstone (specifically Arkose or Quartz Arenite)
Arenite (primarily SiO2 with possible Feldspar)
sedimentary
Banded Calcite (often commercially sold as 'Mexican Onyx' or 'Honey Onyx')
Calcite (Calcium Carbonate, CaCO3)
sedimentary
Chert / Flint
Silicon Dioxide (SiO2)
sedimentary
Polished amethyst bead fragments
Amethyst, purple quartz (SiO₂)
gemstone
Chert (Arrowhead Fragment)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (specifically Black Chert or Flint)
Cryptocrystalline Quartz (SiO2)
sedimentary
Likely weathered iron-rich rock or slag fragment
Uncertain; possibly limonite/goethite-rich material (FeO(OH)·nH₂O)
mineral
Coquina
Biogenic Limestone (Calcite/Aragonite base, CaCO3)
sedimentary
Sandstone
Arenite (siliciclastic sedimentary rock composed mostly of quartz)
sedimentary
Pearl
Pearl (Calcium Carbonate with organic conchiolin, CaCO3)
mineral
Chert (specifically Jasper or Flint variety)
Cryptocrystalline Quartz (SiO2)
sedimentary
Granite
Phaneritic Igneous Rock (composed mostly of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Diamond (Faceted)
Carbon (C)
gemstone
Chert Arrowhead (Lithic Tool)
Microcrystalline quartz (SiO2) - Archeological lithic artifact
sedimentary
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Goldstone
Avventurina (Cu + SiO2 glass)
mineral
Diamond
Carbon (C)
gemstone
Beaded gemstone jewelry (likely amethyst, lapis lazuli, and pearl or glass imitation)
Mixed mineral beads; possible quartz (SiO₂) and lazurite-bearing lapis lazuli
gemstone
Possible basalt or iron-rich slag
Basalt (tentative; identification uncertain from image)
igneous
Coquina
Bioclastic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Mother of Pearl (Nacre)
Calcium Carbonate (primarily aragonite, with conchiolin)
Organic Gemstone/Biomineral
Marble
Recrystallized Calcite (CaCO3)
metamorphic