Anthropogenic Material (Man Made Sedimentary Mimic)

Chert

Microcrystalline Quartz (SiO2)

Carved quartz skull, likely smoky quartz or gray chalcedony

Silicon dioxide (SiO₂), quartz or microcrystalline quartz

Coquina

Bioclastic Limestone (Calcium Carbonate, CaCO3)

Coquina

Biogenic Limestone (Calcite/Aragonite base, CaCO3)

Slate

Metamorphic Pelitic Rock

Boxwork Quartz / Septarian Jasper

Boxwork (SiO2 with iron oxide inclusions)

Vesicular basalt (possibly slag-contaminated)

Basalt; chiefly plagioclase and pyroxene, with possible olivine and secondary minerals

Nephrite Jade

Nephrite

Blue chalcedony cabochon (likely)

Chalcedony, microcrystalline SiO₂; possibly blue agate or common opal, which cannot be distinguished confidently from the image

Chert (Flinty variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Goldstone (blue/black aventurine glass)

Man-made aventurine glass; silica glass containing metallic copper or other glittering inclusions

Chert

Microcrystalline Quartz (SiO2)

Green Aventurine

Quartzite with Fuchsite (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)

Flint

Silicon Dioxide (SiO2) - Chert variety

Polished blue-green glassy slag or coated mineral fragment

Most likely man-made colored glass/slag; exact composition cannot be determined visually

Crushed Limestone

Calcium Carbonate (CaCO3)

Diamond

Carbon (C)

Carved labradorite fish

Labradorite, calcium-rich plagioclase feldspar (approximately (Ca,Na)(Al,Si)₄O₈)

Banded Agate (Mutton-fat or Pork-stone variety)

Silicon Dioxide (SiO2) with iron oxide inclusions

Chert (specifically Jasper or Flint variety)

Cryptocrystalline Quartz (SiO2)

Chert with Manganese Dendrites / River Silt Overlays

Cryptocrystalline Quartz (SiO2) with Manganese Oxides

Chert

Microcrystalline Quartz (SiO2)

Chalcedony (likely blue agate) knapped into an arrowhead

Microcrystalline quartz, SiO₂ (chalcedony)

Polished amethyst-bearing quartz

Quartz, SiO₂; purple coloration from irradiation and trace iron

Yellow faceted gemstone, likely citrine or synthetic glass

Citrine (quartz, SiO₂) is the leading natural possibility; visual identification is uncertain from the photograph

Chert (Flint)

Chert (Microcrystalline or cryptocrystalline Quartz - SiO2)

Chert (specifically Zebra Chert/Flint)

Silicon Dioxide (SiO2)

Colorless faceted gemstone, likely glass or cubic zirconia

Uncertain; possible cubic zirconia (ZrO₂) or quartz (SiO₂), but the image may show a man-made simulant

Red coral (likely precious coral)

Corallium sp.; calcium-carbonate skeleton, primarily calcite

Chert

Chert (Microcrystalline Quartz)

Chalk

Calcium Carbonate (CaCO3)

Iron-rich meteorite (probable stony-iron or weathered iron meteorite)

Unclassified meteorite; likely Fe–Ni metal with silicate minerals

Diamond (as set in a gold ring)

Carbon (C)

Slag (Industrial Byproduct)

Ferro-silicate glass (Slag)

Sea Glass (Uranium/Vaseline Glass variant)

Silicon Dioxide (SiO2) with trace Uranium Oxide (U3O8)

Trilobite fossil

Trilobita (exact species indeterminable from the image)

Turquoise

Hydrated phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O

Chert (Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Onyx (Black) and Mother of Pearl Inlay

Silicon Dioxide (SiO2) for Onyx; Aragonite (CaCO3) for Mother of Pearl

Chert (Iron-stained)

Chert (Microcrystalline and Cryptocrystalline Quartz, SiO2)

Chert (Flint)

Chert (Microcrystalline Quartz, SiO2)

Sea Glass (Teal/Turquoise)

Amorphous Silica (SiO2) with trace metal oxides