Metamorphic Or Sedimentary Depending On Local Grade

Weathered greenstone pebble

Metamorphosed mafic rock, commonly metabasalt or greenschist (exact identification requires testing)

Weathered quartz-rich metamorphic rock, likely quartzite or gneiss

Quartzite/gneiss; chiefly quartz (SiO₂) with feldspar and mica/iron oxides

Conglomerate

Conglomerate Rock

Banded chert or siliceous shale

Microcrystalline quartz (SiO₂), possibly interbedded with carbonaceous or clay-rich shale

Clear Quartz (Faceted)

Silicon Dioxide (SiO2)

Blue Sapphire

Corundum (Al2O3)

Red Jasper

SiO2 (Microcrystalline Quartz)

Slate

Slate; predominantly fine-grained phyllosilicates, commonly muscovite/illite and chlorite with quartz

Gneiss (River Cobble)

Metamorphic Gneiss

Emerald (likely faceted gemstone)

Beryl, Be₃Al₂Si₆O₁₈; green color typically from chromium and/or vanadium

Gneiss

Gneiss (High-grade metamorphic rock)

Slate

Slate (foliated metamorphic rock)

Jade (likely Nephrite Jade based on appearance)

Nephrite (a variety of actinolite, Ca2(Mg,Fe)5Si8O22(OH)2)

Banded dark pebble (likely gneiss or banded metamorphic rock)

Indeterminate from the image; possibly banded gneiss

Banded gneiss

Gneiss, commonly quartz–feldspar–mica gneiss

Gneiss

Gneiss

Riverstone (likely Gray Slate or Siltstone)

Metamorphosed fine-grained sedimentary rock (Argillite/Slate)

Gneiss

Gneiss

Gneiss

Gneiss

Flint or chert nodule

Microcrystalline quartz (SiO₂), commonly chalcedony with possible opal and impurities

Banded Gneiss

Gneiss (Metamorphic Rock)

Banded Gneiss

Gneiss (Metamorphic Rock)

Rounded brown pebble, likely weathered basalt or iron-rich volcanic rock

Indeterminate fine-grained mafic rock; possible basalt (plagioclase–pyroxene ± iron oxides)

Red jasper chips

Jasper, microcrystalline quartz (SiO₂) colored mainly by iron oxides

Weathered rock with a tan mineral vein or inclusion

Indeterminate from the photograph; possibly a quartz- or feldspar-rich vein in dark metamorphic host rock

Quartz-rich metallic-looking pebble

Likely quartz or quartzite; exact identification is uncertain from the blurred image

Dark slate pebble

Slate, predominantly fine-grained mica and clay-derived minerals

Green schist (probable chlorite–actinolite schist)

Chlorite–actinolite schist; commonly composed of chlorite, actinolite, epidote, albite, and quartz

Biotite Schist

Biotite Schist

Polished golden-brown banded stone, likely tiger’s eye

Tiger’s eye (quartz with fibrous crocidolite pseudomorphs; SiO₂)

Polished greenstone (likely serpentinite or soapstone)

Serpentinite, chiefly antigorite/lizardite; possibly talc-rich steatite

Gneiss

Metamorphic Gneiss (High-grade regional metamorphism)

Gneiss

Gneiss (High-grade Metamorphic Rock)

Banded gneiss

Quartz–feldspar gneiss, possibly biotite-bearing; exact identification requires testing

Ruby

Corundum (Al2O3 with Chromium traces)

Anthracite Coal

Anthracite (Metamorphic/High-grade Coal)

Garnet Schist

Almandine-mica schist

Blue Calcite

Calcium Carbonate (CaCO3)

Ironstone Concretion

Siderite or Limonite Concretion (FeCO3 or FeO(OH)·nH2O)

Quartzite

Metamorphic Quartz Sandstone

Brecciated jasper with quartz/chalcedony

Jasper (microcrystalline quartz, SiO₂), with chalcedony and iron-oxide matrix

Chert Arrowhead (Projectile Point)

Chert (Cryptocrystalline Quartz, SiO2)