Anthropogenic Sedimentary (Man Made)

Blue Chalcedony Cube

Silicon Dioxide (SiO2)

Conglomeratic gravel / polymictic breccia

Polymictic rudite, likely anthropogenic or beach/stream gravel; composition varies

Chalk

Calcium Carbonate (CaCO3)

Sandstone Concretion

Sedimentary concretion

Jewelry Chain with Blue and Clear Gemstones (Likely Cubic Zirconia)

Cubic Zirconia (ZrO₂), Silver or White Gold/Platinum Alloy

Chert (likely flint)

Microcrystalline quartz, SiO₂

Mystic Topaz

Aluminum silicate fluoride hydroxide with titanium coating (Al2SiO4(F,OH)2)

Cupronickel (on a 1981 Mexico 20 Pesos coin)

Copper-Nickel Alloy (Cu75Ni25)

Turquoise

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

Man-made Green Quartz (Lab-grown or Treated)

Silicon Dioxide (SiO2) with artificial coloration

Fossil Shark Tooth

Lamniform (Mackerel Shark) fossil tooth, likely Otodus or Cretalamna

Grey Chalcedony

Silicon Dioxide (SiO2)

Likely weathered metallic mineral or slag fragment

Uncertain; possibly limonite/goethite-coated iron mineral, or industrial iron slag

Basalt

Basalt (Mafic volcanic rock)

Goldstone (blue/black aventurine glass)

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

Small clear crystal, possibly quartz or glass-like gemstone

Uncertain; likely quartz (SiO₂), but the image is insufficient to exclude man-made glass or cubic zirconia

Tiger Shark Fossil Tooth

Galeocerdo cuvier (fossilized)

Possible tektite or volcanic glass specimen

Natural silica glass; composition commonly near SiO₂, but exact identification requires chemical testing

Sandstone

Clastic Sedimentary Rock

Yellow cabochon gemstone, likely citrine or yellow glass imitation

Quartz (SiO₂), if natural citrine; visual evidence is insufficient to exclude man-made glass or resin

Polished green-and-black banded cabochon (likely malachite imitation or dyed agate)

Uncertain; possible malachite (Cu₂CO₃(OH)₂), banded agate (SiO₂), or man-made glass

Green glass cabochon or tumbled stone

Indeterminate; likely man-made glass, possibly aventurine glass rather than a natural mineral

Polished blue-green glassy slag or coated mineral fragment

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

Blue goldstone beads

Man-made aventurine glass (silica glass with metallic copper inclusions), not natural lapis lazuli

Obsidian Arrowhead

Obsidian (Volcanic Glass)

Slag

Anthropogenic Vitreous Silicate / Ferro-silicate Slag

Sandstone

Arenite

Chert

Chert (Microcrystalline Quartz)

Slag (Industrial Byproduct)

Ferro-silicate glass (Slag)

Sea Glass (Frosted Glass)

Amorphous Silica (SiO2) with various additives

Iron Slag

Ferrous slag (primarily silicates and oxides of calcium, iron, and magnesium)

Slag

Ferrous Slag (Siliceous industrial waste)

Sea Glass (Uranium/Vaseline Glass variant)

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

Coquina

Bioclastic Limestone

Coquina

Bioclastic Limestone

Blue chalcedony cabochon (probable)

Chalcedony, a cryptocrystalline variety of quartz; silicon dioxide, SiO₂

Ferrous Slag (Iron Smelting By-product)

Fused Siliceous Slag

Sea Glass (Kelly Green)

Amorphous Silica (Silicon Dioxide with Iron/Chromium additives)

Turquoise (likely stabilized or simulated Howlite)

CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)

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

Colorless faceted quartz-like gemstone

Likely quartz (SiO₂), though the appearance may also indicate man-made glass or cubic zirconia

Fossil Sea Urchin (Echinoid)

Echinoidea fossil (often replaced by silica or calcite)