Anthropogenic (Man Made Material Mimicking Sedimentary Rock)

Chert / Jasper

Silicon Dioxide (SiO2)

Slate

Slate (Foliated Metamorphic Rock)

Weathered quartz-rich rock, possibly chert or milky quartz

Mostly microcrystalline or crystalline quartz (SiO₂), identification uncertain from photograph

Beaded Jewelry (Assorted Gemstones)

Various minerals, including but not limited to Quartz (SiO2), Garnet (X3Y2(SiO4)3), Jade (Na(Al,Fe)Si2O6), Amethyst (SiO2),等の多様な組み合わせ

Slate

Slate (Metamorphic Rock)

Weathered granite or granitic pegmatite cobble

Granite/granitic rock, composed mainly of quartz (SiO₂), feldspar, and minor biotite or other dark minerals; the reddish-brown areas may be iron-oxide staining or weathered accessory minerals

Sandstone (likely Ferruginous)

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

Chert (Yellow Jasper)

Microcrystalline Quartz (SiO2)

Gneiss pebble

Banded gneiss, commonly quartz–feldspar–biotite gneiss

Sandstone with Trace Fossils

Quartz Arenite with Bioturbation (Trace Fossils)

Chert (within Limestone)

Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3) matrix

Fossilized Bivalve Shell

Bivalvia (Phylum Mollusca)

Sandstone Pebble

Arenite (SiO2 primarily)

Chert (Flint nodule)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Jasper and Quartz Breccia

Silicified Breccia (SiO2)

Quartz (likely Rose Quartz or Milky Quartz based on color)

Quartz (SiO2 - Silicon Dioxide)

Limonite (Iron-rich Siltstone / Sandstone base)

Hydrous ferric oxide mixture (FeO(OH)·nH2O)

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Carnelian Beads

Silicon Dioxide (Variety of Chalcedony), $SiO_2$

Quartzite Pebbles with Quartz Veining

SiO2 (Silicon Dioxide with country rock matrix)

Breccia

Breccia

Coquina or Fossiliferous Conglomerate

Bioclastic Rudstone (variable composition)

Chert (Jasper/Ironstone variety)

Silicon Dioxide (SiO2) with iron oxide inclusions

Sandstone

Arenite (CaCO3/SiO2 cemented quartz)

Chert (Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Weathered granite (feldspathic, iron-stained granite)

Granite; primarily quartz, potassium feldspar, plagioclase feldspar, and minor mica/amphibole. Exact identification is uncertain from a single photograph.

Sandstone (with Iron Oxidation)

Arenite (SiO2 with Fe-oxides)

Red Sandstone

Arenite (Ferruginous Sandstone)

Jasper / Chert (River Pebble)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Red Sandstone

Arenite (Ferruginous Sandstone)

Chert (often called Flint or Jasper)

Silicon Dioxide (SiO2)

Chert (varieties include Flint and Jasper)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (Agatized)

Silicon Dioxide (SiO2)

Sandstone

Sandstone (Clastic Sedimentary Rock)

Sandstone (specifically Arkose or Ferruginous Sandstone)

Sandstone (SiO2 with iron oxide inclusions)

Conglomerate

Conglomerate (clastic sedimentary rock type)

Weathered granitic rock

Granite or granodiorite; mainly quartz, feldspar, and mica/amphibole

Quartz pebble (Quartzite / Chert)

Silicon Dioxide (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Red Sandstone

Arenite with Hematite (Fe2O3)

Sandstone (Ferruginous)

Arenite (Fe-rich)

Chert (Flint)

Chert (Microcrystalline Quartz, SiO2)