Man Made Material, Not A Natural Rock Or Mineral Specimen

Tumbled quartz pebble

Quartz (silicon dioxide, SiO₂)

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Sandstone

Arenite

Diamond

Natural Diamond (Carbon, C)

Diamond

Carbon (C)

Pale green tumbled mineral fragment, likely serpentine or green calcite

Probable serpentine-group mineral (Mg3Si2O5(OH)4) or, less likely, calcite (CaCO3); identification is uncertain from the photograph

Sandstone with Mineral Veining or Crust

Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)

Blue quartzite or blue aventurine glass-like aggregate

Quartzite, predominantly SiO₂ (identification uncertain from image)

Sandstone

Arenite

Porphyry

Porphyritic Andesite / Basaltic Porphyry

Green Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2AlSi3O10(OH)2)

Shale

Argillite / Shale

Sandstone

Arenite

Sandstone (Stream-rounded)

Arenite (SiO2 based)

Quartz-veined Diabase or Basalt Pebble

Diabase or Basalt with Hydrothermal Quartz Veins (SiO2)

Unakite-like granite with a white feldspar inclusion

Granite, chiefly quartz–feldspar–biotite; pale inclusion likely albite/orthoclase feldspar

Slate

Metamorphic Pelitic Rock

Slate

Metamorphic Pelitic Rock

Sandstone (Pebble)

Arenite (composed primarily of SiO2)

Sandstone (Ferruginous)

Arenite (composed primarily of SiO2 with Fe2O3 cement)

Diamond (or Diamond Simulant)

Carbon (C)

Small tumbled dark stone, possibly basalt or slag

Likely fine-grained basalt; exact identification is uncertain from the photograph

Sandstone (likely Ferruginous)

Arenite (SiO2 based with Fe2O3/FeO(OH) cement)

Jasper-bearing Quartzite River Cobble

Tectonized Quartzite with Iron-Oxide (Hematite/Limonite) Veining

Sandstone

Arenite (Siliclastic sedimentary rock)

Blue glass-like gemstone specimen (likely dyed or synthetic quartz)

Uncertain; possibly blue-dyed quartz or synthetic glass, not confidently identifiable from the image

Sandstone

Arenite (Siliclastic sedimentary rock)

Sandstone

Sandstone (Quartz-rich sedimentary rock)

Flint / Chert

Microcrystalline Quartz (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Tumbled green aventurine

Quartzite dominated by quartz (SiO₂), with green mica/fuchsite inclusions

Sandstone

Arenite (primarily SiO2)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Amethyst quartz cluster

Quartz, SiO₂; purple color caused mainly by iron-related defects and irradiation

Tumbled quartz-rich stone, possibly blue quartz or granite

Quartz (SiO₂), with probable feldspar and dark accessory minerals

Sandstone

Arenite (SiO2 primarily)

Sandstone Pebble

Arenite (SiO2 based)

Yellow Ochre / Limonite

Limonite (inter-mixed iron oxides and hydroxides, primarily FeO(OH)·nH2O)

Vesicular basalt (likely weathered lava rock)

Basalt, predominantly calcium-rich plagioclase, pyroxene, and commonly olivine; vesicular texture from gas bubbles

Sandstone (Banded)

Clastic sedimentary rock (primarily SiO2)

Granite

Granite (a plutonic rock)

Agate (Water-Worn)

Cryptocrystalline quartz (SiO2)