Antropogenic (Man Made Material)

Flint / Chert

Microcrystalline Quartz (SiO2)

Tumbled greenstone (likely serpentinite or green jasper)

Serpentinite, commonly dominated by serpentine-group minerals (Mg₃Si₂O₅(OH)₄); exact identification requires testing

Likely weathered iron-rich rock or slag fragment

Uncertain; possibly limonite/goethite-rich material (FeO(OH)·nH₂O)

Faceted Glass (Costume Jewelry)

Amorphous Silicon Dioxide with colorants (Glass)

Blue glass-like tumbled specimen

Most likely cobalt-blue slag glass or manufactured glass; not confidently identifiable as a natural mineral from the image

Sandstone (Pebble)

Sandstone (arenite, arkose, wacke depending on composition)

Porous limestone (likely fossiliferous or weathered limestone)

Calcite-rich limestone; chiefly calcium carbonate (CaCO₃)

Petrified Wood

Silicified Wood (SiO2)

Sandstone

Arenite (siliciclastic sedimentary rock composed mostly of quartz)

Chert (often called Flint)

Microcrystalline Quartz (SiO2)

Sandstone (Red/Brown Variety)

Arenite (composed primarily of SiO2 with Fe2O3 iron oxide inclusions)

Green Glass Cullet / Recycled Glass

Amorphous Silicon Dioxide (SiO2) with various metal oxides

Diamond

Carbon (C)

Blue-beaded gemstone jewelry, likely lapis lazuli or dyed blue agate

Uncertain from the image; possible lazurite-bearing lapis lazuli (Na₃Ca(Si₃Al₃)O₁₂S) or blue chalcedony (SiO₂)

Natural or Cultured Pearl

Calcium Carbonate (Aragonite and Conchiolin), CaCO3

Diamond (or Simulant)

Carbon (C) or Cubic Zirconia (ZrO2)

Diamond (in a jewelry setting)

Carbon (C)

Blue slag glass / industrial smelter slag

Man-made iron-rich silicate slag; composition variable, commonly Fe–Ca–Mg–Al silicates with glassy phases

Chert (Chalcedony/Agate)

Microcrystalline Quartz (SiO2)

Chert / Green Jasper

Silicon Dioxide (SiO2)

Diorite (River Pebble)

Intermediate Phaneritic Igneous Rock

White Marble

Recrystallized Calcite Rock (CaCO3)

Fossilized oyster shell

Bivalvia; likely an oyster (Ostreidae), partly mineralized with calcite

Possible basalt or iron-rich slag

Basalt (tentative; identification uncertain from image)

Flint or chert, possibly a knapped stone tool

Microcrystalline quartz (SiO₂), commonly chalcedony with possible carbonaceous impurities

Diamond

Carbon (C)

Flint (or Chert with cortex)

Silicon dioxide (SiO2)

Chert (varieties include Flint and Mudstone)

Microcrystalline Silica (SiO2)

Tumbled purple chalcedony or low-grade amethyst bead bracelet

Chalcedony (microcrystalline SiO₂), possibly quartz/amethyst; composition is SiO₂

Quartzite

Silica (SiO2) quartzite

Basalt

Basalt

Chert (Chocolate or Brown Flint)

Chert (SiO2)

Artificial Rock Face (Faux Rock)

Glass Fiber Reinforced Concrete (GFRC)

Chalk

Micrite (primarily Calcium Carbonate, CaCO3)

Tumbled purple quartz, likely amethyst or lavender quartz

Quartz (SiO₂), probably iron-colored amethyst; exact variety uncertain from the image

Tumbled amber-colored chalcedony or jasper

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/jasper

Diamond (Faceted)

Carbon (C)

Diamond (in Jewelry Setting)

Carbon (C)

Lapis lazuli and green-blue chalcedony jewelry

Lapis lazuli: lazurite-bearing metamorphic rock, chiefly lazurite (Na₃Ca(Al₃Si₃O₁₂)S) with calcite and pyrite; second stone: likely chrysoprase or green-blue chalcedony (microcrystalline quartz, SiO₂)

Petrified Wood (Silicified Wood)

Silicified Paleoflora (mainly Quartz, SiO2)

Diorite

Diorite

Cardstock (Paper)

Cellulose (C6H10O5)n