Sedimentary Or Metamorphic

Weathered quartz-rich rock, likely chert or quartzite

Microcrystalline quartz (SiO₂), possibly with iron-oxide staining

Weathered iron-rich stone, possibly chert or quartzite

Indeterminate; likely silica-rich rock with iron-oxide staining (SiO₂-dominant)

Banded Chert / Banded Jasper (likely a variety of Chert/Chalcedony)

Chert (microcrystalline quartz)

Tumbled reddish-brown stone, possibly jasper or iron-rich quartzite

Uncertain from image; likely microcrystalline quartz (SiO₂) with iron-oxide inclusions

Pyrite (or Fool's Gold)

Pyrite (FeS₂)

Tumbled golden-brown stone, likely sandstone or iron-stained quartzite

Indeterminate from image; probable quartz-rich sandstone (SiO₂) or quartzite

Sandstone, Quartzite, and River Pebbles

Silicon Dioxide (SiO2) based Sedimentary/Metamorphic structures

Quartzite / Sandstone / Chert Mix

Silicon Dioxide (SiO2)

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

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

Jasper

Chalcedony (Microcrystalline Quartz) - SiO2

Probable amber fragment

Amber (fossilized plant resin; chiefly amorphous organic resin, commonly dominated by succinite)

River Stone / Pebble

Clastic Sediment (composed largely of Quartz, Feldspar, and various rock fragments)

Sandstone or Quartzite pebble

Sandstone (Quartz arenite) or Quartzite

Jasper or Red Quartzite

SiO2 (Silicon Dioxide with iron oxide impurities)

Banded Sandstone or Quartzite Pebble

SiO2 (dominant) with impurities

Quartz (chalcedony variety) or Limestone with Quartz Veins

SiO2 (for Quartz/Chalcedony); CaCO3 (for Limestone)

Sandstone or Quartzite Pebble

Arenite or Quartzite

Rounded river pebble, likely quartz-rich sandstone or quartzite

Indeterminate; probable quartz (SiO₂) with feldspar, iron-oxide staining, and minor lithic grains

Jasper and Quartzite mix

Silicon Dioxide (SiO2) with impurities

Tiger’s eye

Quartz variety, primarily silicon dioxide (SiO₂); fibrous quartz pseudomorph after crocidolite asbestos

Greenstone / Chert

Cryptocrystalline Quartz (SiO2) or Altered Basalt

Red Jasper (possibly with Quartz or Hematite)

Silicon Dioxide (SiO2) with iron oxide impurities

Rounded brown pebble, likely chert or iron-stained quartzite

Microcrystalline quartz (SiO₂), possibly quartzite; identification is uncertain from the image

Worn quartz-rich pebble, likely chert or quartzite

Microcrystalline quartz (SiO₂), possibly quartzite

Mixed Agate and Lapis Lazuli Bracelet

Chalcedony (SiO2) and Lapis Lazuli (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2

Glacial Erratic (Sandstone/Quartzite)

Glacial Erratic specimen (likely Orthoquartzite or Feldspathic Sandstone)

Limonite-stained Quartz / Quartzite

Silicon Dioxide (SiO2) with iron hydroxides (FeO(OH)·nH2O)

Rounded quartz-rich pebble, likely sandstone or quartzite

Quartz sandstone (quartz arenite) or low-grade quartzite; predominantly SiO₂

Smooth river pebble, likely quartz-rich sandstone or quartzite

Indeterminate quartz-rich clast; possibly quartzite (mostly SiO₂)

Sandstone or Quartzite with algae

Unknown specific, largely SiO2 with biological growth

Rounded river pebble, likely quartz-rich sandstone or fine-grained quartzite

Indeterminate quartz-rich lithic clast; likely quartz sandstone (SiO₂-rich) or quartzite

Weathered quartz-rich rock, likely sandstone or quartzite

Quartz-dominated lithic fragment; probable quartz sandstone (SiO₂)

Tumbled brown stone, likely jasper or fine-grained quartzite

Uncertain; probable microcrystalline quartz (SiO₂), possibly ferruginous jasper

River Pebbles (Sandstone and Quartzite)

SiO2 (Quartz) dominated clastic rocks

Micaceous Sandstone or Quartzite

Sandstone (lithified quartz grains, often with mica) or Quartzite (metamorphosed sandstone)

River Pebble (likely Quartzite or Chert)

Silicon Dioxide (SiO2) crystal conglomerate

Unidentified River Rock or Mudstone

N/A (Generic rock fragment)

Pyrite-bearing rock (likely pyrite in a quartz or sulfide-rich matrix)

Pyrite, FeS₂; the gray host may be quartz, carbonate, or another sulfide-bearing rock

Rhodonite

Rhodonite, manganese inosilicate — MnSiO₃; the specimen may include quartz, feldspar, and black manganese-oxide minerals in the matrix

Quartz (likely) / Siliceous rock with quartz phenocrysts (if a rock fragment)

Quartz (SiO₂)

Quartz with Iron Stains

Quartz (SiO2) with iron oxide/hydroxide staining

Chalcedony (Banded/Mottled Variety)

Chalcedony (a cryptocrystalline variety of Quartz, SiO2)