Anthropogenic (Man Made Material Processed By Nature)

Quartz Arenite / Sandstone

Quartz sandstone (SiO2 rich clastic sedimentary rock)

Sandstone

Clastic sedimentary rock (Quartz arenite or arkose)

Sandstone (Banded)

Arenite (primarily SiO2)

Sandstone (Ferruginous)

Arenite (Fe-rich)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Sandstone (with vugs or solution cavities)

Arenite (primarily Quartz and Feldspar with CaCO3 or SiO2 cement)

Massive Quartz

Silicon dioxide (SiO2)

Marble (Sculpted Statue)

Metamorphic Limestone (composed primarily of Calcite, CaCO3)

Turquoise

Hydrated copper aluminum phosphate (CuAl6(PO4)4(OH)8·4H2O)

Turquoise

Turquoise - CuAl6(PO4)4(OH)8·4H2O

Sandstone (Ferruginous)

Arenite (Fe2O3 enriched)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Polished brown jasper (likely ocean or brecciated jasper)

Microcrystalline quartz/chalcedony, SiO₂, colored mainly by iron oxides

Limestone

Calcium Carbonate (CaCO3)

Olivine (Peridotite / Dunite Pebble)

(Mg,Fe)2SiO4 (Magnesium Iron Silicate)

Peridotite (Olivine Rock)

Peridotite (composed largely of olivine, (Mg, Fe)2SiO4)

Peridot in Matrix

Olivine ((Mg,Fe)2SiO4)

Quartz-rich feldspathic pebble, possibly granite or granitic gneiss

Quartz–feldspar aggregate, likely granite; dark inclusion may be biotite, hornblende, or iron-oxide staining

Vesicular quartz-rich rock, possibly weathered rhyolite or hydrothermal quartz

Likely quartz (SiO₂) with altered feldspar, iron oxides, and cavities; exact identification requires testing

Likely weathered gray-green stone, possibly serpentinite

Serpentinite (predominantly serpentine-group minerals; identification uncertain from image)

Iron-rich quartzite or ironstone

Ferruginous quartzite; chiefly quartz (SiO₂) with iron oxides such as hematite and goethite

Pale blue-gray quartz-rich pebble (tentative)

Quartz, SiO₂, possibly chalcedony or a weathered metamorphic fragment

Quartz-bearing iron-stained breccia

Brecciated quartz/quartzite with iron oxides, chiefly SiO₂ with hematite/goethite and possible feldspar or host-rock fragments

Pale rounded quartz-rich pebble, likely quartzite

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

Weathered limestone or calcareous sandstone

Calcite-rich carbonate rock, chiefly calcium carbonate (CaCO₃), possibly fossiliferous limestone

River Stone (likely Quartzite or Limestone)

Silicon dioxide (SiO2) or Calcium carbonate (CaCO3)

Marble

Recrystallized Calcite (CaCO3)

Serpentine

Serpentine Group (Mg3Si2O5(OH)4)

Diamond (as featured in jewelry)

Diamond (C - pure carbon)

Dark basalt or basaltic volcanic rock

Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase feldspar, pyroxene, and often olivine

Tumbled hematite-rich jasper

Jasper (microcrystalline quartz, SiO₂) with iron oxides, chiefly hematite (Fe₂O₃)

Translucent agate/chalcedony

Microcrystalline quartz (SiO₂), likely chalcedony with agate-like banding

Orange chalcedony or weathered quartz pebble

Microcrystalline quartz, SiO₂; possibly iron-oxide-stained chalcedony

Chert (Flint)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert

Chert (Microcrystalline Quartz, SiO2)

Quartz with impurities or Host Rock

SiO2 (Silicon Dioxide) with mixed silicates

Rhodonite

Rhodonite ((Mn2+,Fe2+,Mg,Ca)SiO3)

Rhodonite

Manganese Inosilicate (Mn,Fe,Mg,Ca)SiO3

Citrine Quartz

Silicon Dioxide (SiO2)

Blue Dyed Agate

Silicon Dioxide (SiO2) with artificial pigment

Quartz (Citrine variety)

Silicon Dioxide (SiO2)

Turquoise

Hydrated copper aluminum phosphate, CuAl6(PO4)4(OH)8·4H2O