Sedimentary Or Igneous Fragment

Granite fragment

Felsic intrusive igneous rock; mainly quartz, alkali feldspar, plagioclase, and minor biotite/hornblende

Granite fragment

Granite (Felsic intrusive igneous rock)

Chalcedony Geode Fragment

Silicon Dioxide (SiO2)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz (Milky or Cloudy variety)

Silicon Dioxide (SiO2)

Unidentified tan rock fragment

Likely limestone or calcareous sandstone; exact identification requires testing

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Drupa or Druzy Quartz on Geode Fragment

Crystalline Silicon Dioxide (SiO2)

Pebble / Gravel Fragment

Clastic Rock Fragment

River Pebble

Siliceous rock fragment

Quartz

Silicon Dioxide (SiO2)

Fossilized Shark Tooth (Fragment)

Elasmobranchii gen. et sp. indet.

Weathered sandstone or iron-rich sedimentary fragment

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

Concrete fragment with Aggregate

Anthropogenic Concrete with Calcarious and Siliceous Aggregate

Fossiliferous Limestone with Crinoid Stem

Sedimentary Rock with Echinodermata fossil fragment

Milky Quartz with Matrix

Silicon Dioxide (SiO2)

Agate (Fortification Agate)

Banded Chalcedony (SiO2)

Amethyst

Amethyst (SiO2 - Silicon Dioxide with iron impurities)

Chert (Arrowhead Fragment)

Microcrystalline Quartz (SiO2)

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Weathered granite or granitic gneiss fragment

Coarse quartz–feldspar–mica aggregate; possibly weakly foliated gneiss

Quartz Pebble

Silicon Dioxide (SiO2)

Basalt Fragment

Basalt (Aphanitic Mafic Igneous Rock)

Granite Fragment

Felsic Plutonic Rock (Granite)

Granite fragment

Phaneritic Igneous Rock (Granitic composition)

Quartz Geode / Druzy Quartz

Silicon Dioxide (SiO2)

Milky quartz

Quartz, silicon dioxide (SiO₂)

Gneiss

Gneiss

River Pebble

Weathered Rock Fragment

River Pebble

Siliceous rock fragment

Common Brown Pebble

Weathered Rock Fragment

Fossiliferous Shale

Fossiliferous Mudstone / Shale

Quartzite (or Chert/Flint gravel)

Quartzite (SiO2 with iron oxide inclusions)

Iron-rich brown stone, possibly weathered chert or ironstone

Undetermined; likely iron-oxide-bearing silica-rich rock (chert/ironstone)

River Pebble

Polished Quartzite or Mixed Lithology

Likely calcite or quartz fragment

Uncertain from image; calcite (CaCO₃) is the leading possibility, with quartz (SiO₂) another possibility

Chert

Microcrystalline or cryptocrystalline quartz (SiO2)

Sandstone Concretion

Ferruginous Sandstone Concretion

Quartz Pebble

Silicon Dioxide (SiO2)

Pebble

Lithified rock fragment / Sedimentary clast

Quartz-rich rock fragment, possibly granite or quartzite

Primarily quartz (SiO₂), with possible feldspar and iron-oxide staining