Anthropogenic Material (Man Made Sedimentary Mimic)

Opalite

Synthetic Opalised Glass

Slag

Ferrous Slag (Siliceous industrial waste)

Chert (Arrowhead Preform or Point)

Chert (Microcrystalline Quartz, SiO2)

Chert

Microcrystalline Quartz (SiO2)

Green Aventurine

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

Slate

Metamorphic Pelitic Rock

Chert (Flint)

Silicon Dioxide (SiO2)

Sea Glass

Amorphous silicon dioxide (Man-made glass weathered by nature)

Unidentified gray stone/concrete-like fragment

Indeterminate; likely a fine-grained carbonate or cementitious geological fragment

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

Blue glassy tumbled stone, likely blue chalcedony or slag glass

Chalcedony (microcrystalline SiO₂), possibly man-made blue glass

Green sea glass (likely bottle glass)

Man-made soda-lime silicate glass; not a natural mineral

Chert / Flint

Silicon Dioxide (SiO2)

Banded Sandstone (Liesegang Rings)

Sedimentary sandstone with Iron oxide precipitates

Fossil bone, possibly a large mammal long-bone fragment

Fossilized cortical bone; taxon indeterminate from the photograph

Tumbled cream-colored pebble

Likely quartz-rich sandstone or limestone; exact identification requires testing

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

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

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Titanium Amethyst Geode

Silicon Dioxide (SiO2) with Titanium/Metal Vapor Deposition Layer

Blue goldstone beads

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

Howlite (White Buffalo Turquoise)

Howlite (Calcium Borosilicate Hydroxide), Ca2B5SiO9(OH)5

Green glass sphere/marble

Soda-lime glass (primarily SiO2, Na2O, CaO)

Chert (Chalcedony/Agate variety)

Silicon Dioxide (SiO2)

Gastropod Fossil (Steinkern)

Class Gastropoda (internal mold)

Green Glass (often marketed as 'Obsidian' or 'Green Quartz')

Amorphous Silica (SiO2) with copper or chromium additives

Jasper / Chert (Red)

Cryptocrystalline quartz (SiO2)

Sandstone

Arenite (with iron oxide cement)

Chert (Flint)

Silicon Dioxide (SiO2)

Chert

Chert (SiO2)

Chert (Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

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

Sandstone

Arenite (composed primarily of SiO2)

Weathered concrete or cementitious slab (not natural rock)

Artificial calcium-silicate cement composite; likely Portland cement concrete

Dyed Blue Agate (Dragon Vein Agate)

Silicon Dioxide (SiO2) with artificial cobalt/organic dyes

Granite with Cupules / Bedrock Mortars

Granite (felsic intrusive plutonic rock)

Carved Stone Turtle

Carved Soapstone and Quartz

Ferruginous Sandstone Pebble

Arenite with Iron-Oxide Cement (SiO2 with Fe2O3/FeO(OH) staining)

Chert

Microcrystalline silica (SiO2)

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

Slag (Industrial By-product)

Anthropogenic Vitreous Silica/Iron Silicate

Sandstone

Arenite