Industrial By Product

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Small white mineral fragment

Likely quartz (SiO₂), possibly calcite (CaCO₃)

Pumice

Pumicite

Pumice

Pumice (a highly vesicular amorphous silicate glass)

Pumice

Pumice (Volcanic Glass)

Quartzite

Metamorphic Quartzite

Kyanite

Kyanite (Al2SiO5)

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

Limestone

Calcium Carbonate (CaCO3)

Quartzite Cobble with Iron Staining

Metamorphosed Quartz Sandstone (SiO2)

Dragon Vein Agate (Dyed/Treated)

Agate (SiO2)

Specular Hematite (Specularite)

Iron(III) oxide (Fe2O3)

Tumbled howlite (likely)

Howlite, Ca₂B₅SiO₉(OH)₅

Scoria (Lava Rock)

Scoria (Extrusive Igneous Rock / Mafic Silicates)

Sea Glass

Amorphous Silica (Glass) SiO2

Sandstone (with Lichen)

Arenite (primarily SiO2)

Common Gravel / Pebble

Lithified rock fragment / Detrital sediment

Tumbled black stone, likely basalt or black jasper

Probably basalt (fine-grained plagioclase–pyroxene rock); exact identification is uncertain from the image

Sea Glass

Man-made silicate glass (Amorphous silicon dioxide)

Hematite (Iron Ore)

Iron(III) oxide (Fe2O3)

Rhodochrosite

Manganese carbonate (MnCO3)

Hematite

Iron(III) oxide (Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Sulfur-bearing iron ore, likely pyrite-rich gossan

Pyrite (FeS₂) with iron oxides/hydroxides and dark host rock

Weathered granite or granitic gneiss

Granite, chiefly quartz–feldspar–mica; possibly weakly gneissic

Polished dark pebble, likely basalt

Basalt; mainly plagioclase feldspar, pyroxene, and minor olivine or magnetite

Tumbled yellow-green serpentine (probable)

Serpentine-group minerals, chiefly antigorite/lizardite; commonly Mg₃Si₂O₅(OH)₄

Weathered granite

Granite; interlocking quartz–feldspar–mica aggregate

Sandstone / Weathered Chert

Silicon Dioxide (SiO2) / Quartz-rich Clastic Rock

Limestone

Calcium Carbonate (CaCO3)

Weathered quartz-rich rock, possibly quartzite or silicified breccia

Quartzite (predominantly SiO₂); exact identification requires a fresh surface and tests

Green iridescent glass cabochon or synthetic gemstone

Likely synthetic glass; possibly coated synthetic quartz or lab-created green gemstone

Polished red granite or rhyolite pebble

Likely pink/red granite, composed chiefly of quartz, alkali feldspar, and mica; exact identification requires testing

Greenstone (Greenschist facies)

Greenschist (composed primarily of Chlorite, Actinolite, and Epidote)

Weathered granitic rock fragment

Likely granite or granodiorite, composed mainly of quartz, feldspar, and mica

Pyrite (likely)

Iron disulfide, FeS₂; commonly called fool’s gold

Hematite

Iron(III) oxide (Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Hematite

Hematite (Fe2O3)

Turquoise and Hematite

Turquoise (CuAl6(PO4)4(OH)8·4H2O) and Hematite (Fe2O3)

Limonite and Goethite encrusted Chert/Ironstone

Hydrated Iron Oxide (FeO(OH)·nH2O) with cryptocrystalline Silica (SiO2)