Organic Material (Likely A Fruit Or Berry)

Sandstone (likely Arkose or Quartz Sandstone)

Clastic sedimentary rock (primarily SiO2)

Jasper (Green/Yellow Moss Jasper)

Silicon Dioxide (SiO2)

Chert Pebble

Chert (composed primarily of Microcrystalline Quartz, SiO2)

Banded Chert (River Stone/Cobble)

Microcrystalline Quartz (SiO2)

Polished turquoise

Turquoise — hydrated copper–aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O

Sandstone (Quartzose)

Arenite (SiO2 based typically)

Weathered sandstone or iron-stained sedimentary pebble

Quartz-rich sandstone; exact identification requires a fresh surface and tests

Chert (Flint)

Silicon Dioxide (SiO2)

Schist

Mica Schist

Chert Pebble (Flint)

Microcrystalline/Cryptocrystalline Quartz (SiO2)

Gneiss pebble

Banded gneiss, commonly quartz–feldspar–biotite gneiss

Iron-rich laterite or limonite/goethite-bearing rock

Hydrated iron oxides, chiefly goethite (α-FeO(OH)) and limonite (FeO(OH)·nH₂O), likely in a lateritic matrix

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Vesicular basalt (likely amygdaloidal basalt)

Basalt, a mafic volcanic rock composed mainly of plagioclase feldspar, clinopyroxene, and commonly olivine; vesicles are partly mineral-filled amygdules.

Sandstone (likely Arkosic or Lithic)

Clastic Sedimentary Rock (composed mostly of SiO2)

Weathered quartz-rich rock, possibly chert or quartzite fragment

Indeterminate; likely microcrystalline quartz (SiO₂), possibly with iron-oxide staining

Iron-rich vesicular rock, possibly slag or basalt

Uncertain; likely basaltic rock (plagioclase–pyroxene–iron oxide) or industrial iron slag

Tumbled milky quartz (probable)

Quartz, silicon dioxide (SiO₂)

Pale rounded quartz-rich pebble, likely quartzite

Quartzite (mostly microcrystalline SiO₂), possibly quartz-rich sandstone or vein quartz

Sandstone (Ferruginous)

Clastic sedimentary rock (primarily SiO2 with Fe2O3 cement)

Quartz (Water-worn pebble)

Silicon Dioxide (SiO2)

White quartz in dark matrix (likely quartz-bearing breccia or polished composite specimen)

Quartz, SiO₂, in an unidentified dark silicate matrix

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)

Chert / Pink Flint

Cryptocrystalline Quartz (SiO2)

Chert or flint fragment

Microcrystalline quartz (SiO₂), likely silicified rock

Iron-rich flint or chert fragment

Microcrystalline quartz (SiO₂), likely ferruginous chert

Dark rounded stone, possibly basalt or iron-rich chert

Indeterminate from image; candidates include basalt (mafic volcanic rock) or chert (microcrystalline quartz, SiO₂)

Chert (Nodular or Massive Variety)

Cryptocrystalline Quartz (SiO2)

Weathered quartz-bearing rock, possibly granite or gneiss

Indeterminate; likely quartz–feldspar–mica aggregate, possibly granitic gneiss

Basalt

Vesicular Basalt

Quartz-bearing volcanic rock, likely vesicular basalt

Basalt with secondary quartz (SiO₂) and possible zeolite/chalcedony infill

Tumbled feldspar-rich stone, likely granite or granitic pegmatite

Quartz–feldspar aggregate; likely alkali feldspar and plagioclase with minor quartz, possibly altered

Pegmatitic granite

Granite, quartz–feldspar–mica assemblage

Sandstone (likely Arkosic or Quartzose)

Sandstone (SiO2 dominated)

Sandstone (likely Quartzose Sandstone)

Arenite (primarily SiO2)

Weathered brown rock, likely iron-stained sandstone or chert

Indeterminate; probable quartz-rich sandstone/chert with iron-oxide staining

Banded sandstone pebble

Quartz-rich sandstone, likely with a contrasting siltstone or fine-grained sandstone band

Small polished dark mineral or gemstone fragment

Indeterminate; possibly smoky quartz, obsidian, or dark tourmaline

Polished brecciated jasper (likely ribbon jasper)

Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide inclusions

Tumbled green aventurine (likely)

Quartz, SiO₂, containing green fuchsite mica or other inclusions

Tumbled epidote-bearing rock (likely epidote–quartz–feldspar aggregate)

Epidote-rich metamorphic rock; minerals likely epidote (Ca₂(Al,Fe)₃Si₃O₁₂(OH), quartz, feldspar, and dark amphibole/biotite)

Weathered iron-rich rock, possibly limonite-bearing sandstone or laterite

Limonite/goethite-rich ferruginous rock; exact identification requires testing