Metamorphic (Likely Gneiss Or Schist Based On Texture)

Quartz-rich metamorphic pebble, possibly jade-like greenstone

Likely quartzite or altered basalt/greenstone; visible minerals may include quartz, feldspar, chlorite/epidote, and iron oxides

Garnet (Almandine)

Almandine (Fe3Al2(SiO4)3)

Pink Granite

Phaneritic intrusive igneous rock (rich in Potassium Feldspar)

Fuchsite (Chrome Mica)

K(Al,Cr)2(AlSi3O10)(OH)2

Pale rounded quartz-rich pebble, likely quartzite

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

Sandstone

Arenite (primarily SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Quartzite (Gold-Yellow variety)

Quartzite (Silicon Dioxide, SiO2)

Sandstone

Arenite (Secondary classification based on grain size)

Sandstone

Arenite (SiO2 based with mineral cement)

Polygenetic Conglomerate (Puddingstone)

Conglomerate (SiO2 matrix with mixed clasts)

Serpentine

Serpentine Group (Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al)2O5(OH)4

Emerald in Matrix

Emerald (Beryllium Aluminum Silicate), Be3Al2(SiO3)6

Quartzite Pebble

Quartzite (SiO2)

River Stone (likely Quartzite or Sandstone)

Metamorphosed Quartz-rich Rock (SiO2)

Pyrite

Iron Pyrite (FeS2)

Likely basaltic rock fragment

Fine-grained mafic igneous rock, probably basalt (plagioclase–pyroxene ± olivine)

Sandstone (likely Quartzose Sandstone)

Arenite (composed primarily of SiO2)

Banded Slate or Siltstone with Quartz/Calcite Veins

Protolith-derived Siltstone or Slate (varies based on degree of metamorphism)

Green Schist (Greenschist)

Greenschist facies metamorphic rock

Polished Unakite (likely)

Unakite: quartz + epidote + pink K-feldspar, commonly with minor chlorite

Pyrite

Iron Sulfide (FeS2)

Granite

Granite (phaneritic felsic intrusive rock)

Weathered basalt or mafic volcanic rock

Basalt; typically plagioclase feldspar, clinopyroxene, and often olivine or iron oxides

Scoria (Vesicular Basalt)

Vesicular Basalt

Quartzite with Hematite

Metamorphic Quartzite (SiO2 with Fe2O3 inclusions)

Basalt (Weathered River Pebble)

Extrusive Igneous Rock

Green Aventurine

Quartz (SiO2) with fuchsite inclusions

Smoky Quartz

Silicon Dioxide (SiO2)

Banded gneiss pebble

Foliated gneiss, typically quartz–feldspar–mica bearing

Black Tourmaline

Schorl (Sodium Iron Aluminum Borosilicate Hydroxide)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Amazonite

Amazonite (Microcline Feldspar) K(AlSi3O8)

Quartzite (River Cobble)

Quartzite (Metamorphosed Quartz Sandstone, SiO2)

Quartzite with Hematite

Metamorphosed Quartz Sandstone (SiO2 with Fe2O3 inclusions)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Quartz-rich limestone or calcitic marble

Calcite (CaCO₃), possibly with quartz (SiO₂)

Tumbled reddish-brown pebble, likely sandstone or iron-rich quartzite

Probable ferruginous sandstone (quartz-rich; SiO₂ with iron oxides), possibly quartzite

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Basalt with Quartz/Calcite Inclusion

Aphanitic Mafic Igneous Rock (Basalt) with SiO2 or CaCO3 vein

Ruby

Corundum (Al2O3:Cr)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)