Polished, carved gemstone (possibly dyed agate or glass-like material)
Unconfirmed from the image; no specific mineral can be identified reliably
gemstone
Category
Anthropogenic Specimen (Man Made Material)
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Chert (often called Flint)
Chert (Cryptocrystalline Quartz, SiO2)
sedimentary
Polished rutilated quartz cabochon
Quartz (SiO₂) with rutile inclusions (TiO₂)
gemstone
Chert (likely jasper/chalcedony-rich chert)
Microcrystalline quartz, SiO₂
sedimentary
Polished orbicular granite heart
Granite, commonly quartz–alkali feldspar–plagioclase–biotite granite; exact locality-dependent
igneous
Green cabochon gemstone, likely nephrite jade
Nephrite jade—interlocking amphibole fibers, chiefly tremolite-actinolite, Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂
gemstone
Tumbled amethyst quartz
Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation
gemstone
Tumbled chalcedony (likely milky quartz)
Microcrystalline quartz, SiO₂; possibly pale agate or quartzite
mineral
Porcelain (Kaolin-based)
Alumina silicate ceramic (composed primarily of Kaolinite: Al2Si2O5(OH)4)
metamorphic (man-made/engineered)
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Obsidian
Obsidian (Volcanic Glass)
igneous
Chert (and/or Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Diamond (in Jewelry)
Carbon (C)
mineral
Flint / Chert
Microcrystalline quartz (SiO2)
sedimentary
Jasper
Silicon dioxide (SiO2) with impurities
sedimentary
Sandstone
Arenite (SiO2, often with CaCO3 or Fe2O3 cement)
sedimentary
Nickel coin (U.S. currency)
Cupronickel (75% Copper, 25% Nickel alloy)
man-made alloy (metallic)
Chert (Black Chert or Flint)
Silicon Dioxide (SiO2)
sedimentary
Tektite (Indochinite)
Tektite (Amorphous Silica Glass)
igneous
Coquina
Biogenic Limestone (Coquina)
sedimentary
Quartzite
Metamorphic Quartzite
metamorphic
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Red Sandstone
Arenite (Iron-rich)
sedimentary
Chert (variations include Flint/Jasper)
Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (varietal Chalcedony or Flint)
Silicon dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Chert (Flint)
Chert (SiO2)
sedimentary
Carnelian cabochon
Orange-red variety of chalcedony (microcrystalline quartz), SiO₂
gemstone
Coquina
Biogenic Limestone (mostly Calcium Carbonate, CaCO3)
sedimentary
Nephrite Jade
Ca2(Mg,Fe)5Si8O22(OH)2
metamorphic
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Faceted colorless gemstone, likely quartz or glass imitation
Most likely quartz (SiO₂), though the strong glare and visible facet pattern could indicate cubic zirconia or lead glass
gemstone
Chalcedony (Agate / Jasper Specimen)
Silicon Dioxide (SiO2)
mineral
Chalk
Carbonate rock (mainly CaCO3)
sedimentary
Obsidian Arrowhead
Volcanic Glass (Primary composition: SiO2)
igneous
Likely smoky quartz pendant
Smoky quartz, silicon dioxide (SiO₂), quartz variety colored by irradiation-related defects
gemstone
Peanut Wood
Petrified Wood (Silicified Araucaria with Teredo boreholes)
fossil
Red Sandstone
Arenite (Fe2O3 enriched)
sedimentary
Diamond
Carbon (C)
mineral
Green Slag Glass
Amorphous Silicon Dioxide (with metallic impurities)
Igneous (Anthropogenic)
White pebbles (rock material not identifiable from the image)
Undetermined; the smooth, pale pieces could be quartz, quartzite, or another light-colored rock
sedimentary