Sedimentary Rock (Altered)

Pink Anthracite Coal (dyed)

Anthracite Coal (Artificially Colored)

Altered volcanic rock, possibly andesite

Likely porphyritic andesite or dacite with secondary chlorite/epidote and quartz–calcite veins

Weathered porphyritic volcanic rock, likely andesite

Porphyritic andesite (tentative; plagioclase ± pyroxene/amphibole in a fine groundmass)

Greenstone, likely altered basalt

Metabasalt (chlorite–actinolite–epidote assemblage), likely greenschist-facies greenstone

Jasper

Silicon Dioxide (Microcrystalline Quartz, SiO2)

Unakite

Epidotized Granite

Rounded river pebble, likely weathered sandstone or volcanic rock

Indeterminate fine-grained lithic clast; possible sandstone (quartz-rich)

Weathered sandstone or arkose fragment

Quartz-rich clastic sedimentary rock; likely sandstone/arkose (dominantly SiO₂ quartz with feldspar and lithic grains)

Epidote

Epidote (Ca2(Al2,Fe3+)3(SiO4)3(OH))

Red jasper in gray host rock (likely hematite-stained quartzite or rhyolite)

Jasper: microcrystalline quartz (SiO₂), with iron-oxide coloration; exact host uncertain from image

Red Jasper or Ferruginous Chert

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Jasper

Microcrystalline Quartz (SiO2)

Jasper (Banded Jasper / Chert)

Silicon Dioxide (SiO2 with iron oxide inclusions)

Weathered mafic rock, likely basalt

Basalt; primarily plagioclase feldspar, pyroxene, and minor olivine or iron oxides

Yellow Quartz (Citrine / Milky Quartz)

Silicon Dioxide (SiO2)

Brecciated Jasper

Silicon Dioxide (SiO2) with iron impurities

Quartz-rich conglomeratic rock (likely granitic breccia or conglomerate)

Uncertain; quartz–feldspar rock in a fine-grained matrix, possibly weathered granite or polymictic conglomerate

Turquoise

Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)

Unidentified orange-brown rock fragment

Likely weathered iron-rich volcanic rock or ochre-bearing material; exact identification is impossible from the blurred image

Possible weathered sandstone or iron-rich sedimentary rock

Indeterminate; likely quartz-rich sandstone with iron-oxide cement

Tumbled Chalcedony

Quartz (Silicon Dioxide - SiO2)

Rounded gray river pebble

Likely fine-grained quartz-rich sandstone or siltstone; exact identification requires a fresh surface and tests

Quartz with inclusions (likely Chlorite or Hornblende) and country rock

SiO2 (Quartz) with associated ferromagnesian minerals

Fossil bivalve shell

Fossilized or partially mineralized bivalve; exact genus cannot be determined from the image

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

Undetermined; likely Fe-oxide-stained basalt or ferruginous sandstone (hematite/goethite-bearing)

Dyed Agate

SiO2

Painted Rock / Geode Specimen

Silicon Dioxide with artificial pigment coating

Copper Ore / Altered Granodiorite

Cupriferous rock with silicate gangue

Likely weathered iron-rich breccia or jasper

Silicified iron-oxide breccia; exact identification requires testing

Turquoise

CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)

Polished brecciated jasper

Jasper, microcrystalline quartz (SiO₂), with iron-oxide and pale silica-rich fragments

Pink feldspar-rich granite or pegmatite

Potassium-feldspar granite; chiefly microcline/orthoclase (KAlSi₃O₈), quartz, and minor mica

Banded Sandstone / Quartzite with Mineral Veins

Sedimentary rock (Quartz arenite with iron oxide/silica banding)

Rounded dark pebble, possibly weathered basalt

Fine-grained mafic volcanic rock; likely basalt, but identification is uncertain from the photograph

Iron-stained quartz-bearing rock, possibly weathered granite or gneiss

Quartz–feldspar rock with iron-oxide staining; exact identification requires testing

Porphyritic volcanic rock, likely porphyritic andesite

Porphyritic andesite; chiefly plagioclase and pyroxene/amphibole phenocrysts in a fine volcanic groundmass

Unidentified weathered rock fragments

Likely mixed silicate rocks; specific identification requires testing

Foliated metamorphic rock, likely gneiss with amphibolite or chlorite-rich bands

Biotite–quartz–feldspar gneiss, locally mafic amphibolite; mineral composition is uncertain from the photograph

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Purple Dyed Dalmatian Stone

Dyed Peralkaline Trachyte

Quartz-veined altered rock

Likely quartz-bearing metasediment or altered igneous rock; vein mineral: quartz (SiO₂)

Oolitic Chert

Ooidal Microcrystalline Quartz (SiO2)