Anthropogenic Material (Man Made Rock)

Chert (Yellow Jasper/Flint)

Microcrystalline Quartz (SiO2)

Likely weathered iron-rich rock or slag fragment

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

Sea Glass (Kelly Green)

Amorphous Silica (Silicon Dioxide with Iron/Chromium additives)

Vesicular basalt (likely scoria)

Basaltic scoria; predominantly plagioclase, pyroxene, and olivine in a mafic volcanic glass/microcrystalline matrix

Conglomeratic concrete or asphalt aggregate surface with dark bituminous chunks

Polymictic gravel aggregate; dark pieces likely bitumen/asphalt, not a natural rock

White Marble

Recrystallized Calcite Rock (CaCO3)

Granite

Phaneritic plutonic rock (SiO2 typically >69%)

Blue glass-like tumbled specimen

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

Granite

Granite (Felsic Plutonic Rock)

Ferruginous Sandstone (Ironstone)

Clastic Sedimentary Rock (composed of SiO2 with Fe2O3/FeO(OH) cement)

Goldstone (blue-goldstone–style glass) beads

Artificial aventurine glass, typically silica glass with copper inclusions; not a natural mineral

Dyed Quartz Geode

Silicon Dioxide (SiO2) with artificial pigment

Granite Pebble

Granite (Phaneritic intrusive igneous rock comprising Quartz, Feldspar, and Mica)

Pearl necklace

Pearl, primarily aragonite (CaCO₃) and conchiolin

Chert (Chalcedony/Agate)

Microcrystalline Quartz (SiO2)

Polished blue calcite sphere (tentative identification)

Calcite, CaCO₃; blue color generally results from trace impurities or inclusions

Synthetic Marbled Aggregate (Footwear Component)

Ethylene-vinyl acetate (Croslite™)

Chert (Chocolate or Brown Flint)

Chert (SiO2)

Basalt

Basalt

Polished greenstone/serpentine pebble (probable)

Serpentinite, dominated by serpentine-group minerals (lizardite/chrysotile); possible accessory olivine or chlorite

Tumbled ruby-in-zoisite (likely)

Ruby-bearing zoisite; zoisite Ca₂Al₃(SiO₄)₃(OH), corundum ruby Al₂O₃

Sandstone

Arenite (composed primarily of SiO2)

Chipped Glass/Plastic Fragment

Silicon dioxide (SiO2) for glass (amorphous) or various polymer compounds for plastic

Banded Slag Glass (Leland Blue/Frankfort Green style)

Anthropogenic Glass Specimen (Amorphous Silicon Dioxide with impurities)

Green Glass Slag

Amorphous Silicon Dioxide (SiO2) with metal oxide impurities

Green sea glass or green glass-like tumbled material

Amorphous silicate glass; likely anthropogenic soda-lime glass, not a natural mineral

Coquina / Fossiliferous Limestone

Calcareous bioclastic sedimentary rock (CaCO3)

Sandstone (Pebble)

Sandstone (arenite, arkose, wacke depending on composition)

Diorite

Intermediate plutonic igneous rock

Tumbled amber-colored chalcedony or jasper

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

Flint or chert, possibly a knapped stone tool

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

Chert (Arrowhead variety)

Chert (SiO2)

Chert (likely flint)

Microcrystalline quartz, SiO₂

Porous limestone (likely fossiliferous or weathered limestone)

Calcite-rich limestone; chiefly calcium carbonate (CaCO₃)

Likely iron-rich rock or weathered metallic mineral fragment

Uncertain; possibly limonite/goethite or iron-bearing slag

Petrified Wood

Silicified Wood (primarily SiO2)

Chert

Microcrystalline Quartz (SiO2)

Banded Calcite (often sold as 'Mexican Onyx' or 'Green Onyx')

Calcite (Calcium Carbonate, CaCO3)

Tumbled greenstone (likely serpentinite or green jasper)

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

Titanium Aura Quartz (Aura Quartz)

Titanium-coated Silicon Dioxide (SiO2)

Chert (Nodule/Pebble)

Chert (Silicon Dioxide, SiO2)

Sandstone (specifically Arkose or Quartz Arenite)

Arenite (primarily SiO2 with possible Feldspar)