Sedimentary Or Igneous Fragment

Banded Sandstone (Water-worn Pebble)

Arenite with mineral banding

Quartz Geode

Silicon Dioxide (SiO2) within a sedimentary or igneous host

Likely weathered limestone fragment

Limestone, composed mainly of calcite (CaCO₃)

Polished black-and-gold brecciated stone, likely sheen obsidian or brecciated jasper

Probable volcanic glass (obsidian), SiO₂, with iron-oxide or rhyolitic inclusions; exact identification is uncertain from the photograph

Likely bituminous coal or carbon-rich shale fragment

Bituminous coal; predominantly carbon with macerals and minor clay/pyrite

Granite Fragment

Felsic Plutonic Rock (Granite)

Basalt fragment

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

Common Brown Pebble

Weathered Rock Fragment

River Pebble

Siliceous rock fragment

River Pebble

Weathered Rock Fragment

Likely polished dark stone or mineral fragment

Indeterminate; possibly hematite, magnetite, or dark basalt

Small rounded mineral pebble, possibly feldspar or quartz

Uncertain from image; likely a quartz- or feldspar-rich grain

Likely weathered quartz-rich pebble

Quartz (SiO₂), possibly iron-stained quartz or quartzite

Milky quartz

Quartz (silicon dioxide, SiO₂)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz (Milky or Cloudy variety)

Silicon Dioxide (SiO2)

Pyrite

Iron Sulfide (FeS2)

Weathered granite or granitic rock fragment

Granite; chiefly quartz, feldspar, and mica/amphibole

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate (SiO₂ with feldspar minerals)

Weathered quartz-rich pebble

Likely quartzite or silicified granitoid; mainly microcrystalline quartz (SiO₂)

Likely weathered quartz-bearing rock fragment

Indeterminate; possibly granitic or metamorphic quartz–feldspar aggregate

Small pale-yellow stone, likely quartz or quartz-rich pebble

Unidentified silica-rich specimen; possibly quartz (SiO₂)

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Breccia

Clastic Breccia

Tumbled fossiliferous limestone

Micritic limestone, likely bioclastic/fossiliferous carbonate rock (predominantly CaCO₃)

Weathered sandstone or iron-rich sedimentary fragment

Quartz-rich sandstone, possibly ferruginous sandstone (SiO₂-dominant)

Tumbled pale feldspar-rich stone (likely granite or quartzite fragment)

Indeterminate; possible quartz–feldspar aggregate, commonly granite or feldspathic quartzite

Weathered granite or granitic gneiss fragments

Granite; chiefly quartz, feldspar, and biotite/hornblende

Limestone with Fossil Fragments

Bioclastic Limestone (CaCO3)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Drupa or Druzy Quartz on Geode Fragment

Crystalline Silicon Dioxide (SiO2)

Granite Pebble

Granite (composed primarily of Quartz, Feldspar, and Mica)

Fossil Shark Tooth Fragment

Elasmobranchii dentition (fragment)

Quartz fragment

Quartz (silicon dioxide, SiO₂)

Quartz fragment

Silicon Dioxide (SiO2)

Quartz (Druzy or Geode fragment)

Silicon Dioxide (SiO2)

Volcanic tuff and basalt outcrop

Welded volcanic tuff, with probable basaltic lava/scoria

Small weathered stone, likely sandstone or limestone fragment

Indeterminate clastic or carbonate rock; mineral composition cannot be confirmed from the image

Fossiliferous Limestone

Biogenic Sedimentary Rock

Limestone Fragment

Sedimentary rock (primarily Calcium Carbonate, CaCO3)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)