Synthetic (Man Made Glass)

Green obsidian (likely molded or heat-treated glass-like specimen)

Volcanic glass; predominantly rhyolitic composition (silica-rich amorphous SiO₂)

Crushed Stone (Likely Limestone or Granite)

Calcium Carbonate (CaCO3) for Limestone / Quartz and Feldspar for Granite

White cabochon gemstone, likely milky chalcedony or opalite

Chalcedony: microcrystalline quartz, SiO₂; appearance may also indicate synthetic opalite glass

Mystic Topaz (Treated Quartz or Topaz)

Aluminum silicate fluoride hydroxide [Al2SiO4(F,OH)2] with thin-film metallic coating

Sandstone Concretion

Limonitic Sandstone Concretion

Orgonite Pyramid (containing Amethyst and mixed minerals)

Silicon Dioxide (SiO2) in synthetic resin

Polished silver sheen obsidian heart

Obsidian (volcanic glass), primarily rhyolitic silica-rich glass

Polished labradorite pendant

Labradorite, a calcium-rich plagioclase feldspar (approximately NaAlSi₃O₈–CaAl₂Si₂O₈)

Citrine Quartz

Citrine (Silicon Dioxide, SiO2)

Ferrous Slag

Iron/Steel Slag (Complex Calcium-Alumino-Silicates)

Aura Quartz (Rainbow Quartz)

Silicon Dioxide (SiO2) with metallic vapor coatings

Sea Glass

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

Green cabochon gemstone, likely aventurine or dyed chalcedony

Indeterminate from image; possible quartz variety (SiO₂), including aventurine quartz or chalcedony

Colorless quartz crystal (likely quartz fragment)

Quartz, silicon dioxide (SiO₂)

Unidentifiable Rock Fragment

Asphalt Concrete (Bituminous Conglomerate)

Anthropogenic Bituminous Conglomerate

Amethyst gemstone ring

Quartz, purple variety — SiO₂

Concrete Rubble with Aggregate

Hardened Portland Cement Paste with Coarse Aggregate

Concrete

Anthropogenic Conglomerate

Sea Glass

Amorphous Silicon Dioxide (Man-made glass weathered by nature)

Chert Arrowhead (Projectile Point)

Microcrystalline Quartz (Chert or Flint)

Blue Goldstone

Goldstone (artificial glass)

Red goldstone beads

Goldstone (man-made copper-bearing glass; not a natural mineral)

Goldstone (brown goldstone)

Man-made aventurine glass, typically copper-bearing silica glass

Carved labradorite fish

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

Yellow faceted gemstone, likely citrine or synthetic glass

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

Strawberry Quartz

Silicon Dioxide (SiO2) with Hematite/Goethite inclusions

Blue Obsidian

Volcanic Glass (SiO2 with inclusions)

Chert Concretion

Chert (Microcrystalline Quartz, SiO2)

Polished brown jasper (likely brecciated or orbicular jasper)

Microcrystalline quartz/chalcedony, SiO₂, with iron-oxide and other mineral inclusions

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

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

Aggregate Concrete

Anthropogenic Conglomerate (Technosol)

Asphalt Concrete

Bituminous Concrete

Titanium Aura Quartz

Titanium bonded Silicon Dioxide (SiO2 + Ti)

Green sea glass (likely)

Man-made glass, likely soda-lime silicate glass; not a natural mineral or rock

Black Obsidian

Amorphous volcanic glass (SiO2 + impurities)

Tumbled milky chalcedony (likely common opalite-like quartz)

Chalcedony, microcrystalline SiO₂; possibly pale common opal, hydrated SiO₂·nH₂O

Aura Quartz (Titanium Quartz)

Titanium-coated Silicon Dioxide (SiO2 + Ti)

Concretion (Sandstone)

Carbonate-cemented Sandstone Concretion

Glass / Silicon Dioxide (Man-made)

SiO2 (Amorphous Silicon Dioxide)

Blue glassy tumbled stone, likely blue chalcedony or slag glass

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

Cullet (Slag Glass)

Amorphous Silica (Industrial byproduct)