Sedimentary Rock (Metamorphosed)

Blue-gray quartz-rich rock fragment, likely crushed granite or gneiss

Granite–gneiss aggregate; chiefly quartz (SiO₂), feldspar, and mica/amphibole

Quartzite River Rock (with Quartz Vein)

Quartzite (SiO2)

Weathered iron-rich metamorphic rock

Likely iron-stained quartzite or metasedimentary rock; exact identification requires testing

Weathered quartz-rich rock, possibly granite or quartzite

Likely quartz–feldspar aggregate; precise identification requires testing

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly quartz (SiO₂), with minor feldspar, mica, and iron-oxide staining

Weathered granite or granitic gneiss

Quartz–feldspar–mica aggregate; likely granite, possibly foliated gneiss

Tumbled quartz-rich rock, likely granite or granitic gneiss

Granite/granitic gneiss; chiefly quartz (SiO₂), feldspars, and minor mica/amphibole

Iron-stained quartz-rich rock

Likely ferruginous quartzite; chiefly quartz (SiO₂) with iron oxides/hydroxides

Marble

Metamorphosed Limestone (calcite formulation CaCO3)

Weathered iron-rich rock, possibly hematite-bearing quartzite

Quartzite with iron oxides (quartz, hematite/goethite); exact identification requires testing

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly quartz (SiO₂), with minor mica and iron-oxide staining

Tumbled gray-green metamorphic rock, likely serpentinite or chlorite schist

Serpentinite/chlorite-rich ultramafic metamorphic rock; commonly dominated by antigorite, lizardite, or chlorite with minor magnetite and talc

Weathered greenish metamorphic rock, likely serpentinite

Serpentinite, dominated by serpentine-group minerals (commonly antigorite, lizardite, or chrysotile)

Weathered igneous rock fragment, possibly granite or granitic gneiss

Indeterminate; likely quartz–feldspar–mica aggregate (granite), possibly foliated gneiss

Quartzite River Stone

Metamorphosed Quartz-rich Sandstone (SiO2)

Weathered granite or granitic gneiss

Granite; chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende

Blue quartzite or blue schist (likely quartzite)

Quartz-rich metamorphic rock; predominantly SiO₂, possibly with blue amphibole or dumortierite

Serpentinized ultramafic rock (likely serpentinite)

Serpentinite; chiefly serpentine-group minerals (chrysotile, lizardite, antigorite), with olivine/pyroxene relics and possible magnetite

Serpentinized ultramafic rock (likely serpentinite)

Serpentinite; chiefly serpentine-group minerals, with possible magnetite, olivine, pyroxene, and talc

Rounded river pebble, likely sandstone or weathered quartzite

Indeterminate lithic clast; probable quartz-rich sandstone (SiO₂-dominant)

Quartz-rich sandstone or quartzite cobble

Quartz arenite; possibly weakly metamorphosed quartzite (SiO₂-dominant)

Granite or granitic gneiss fragment

Granite; primarily quartz, feldspar, and mica

Tumbled quartz-rich pebble, possibly jasper or quartzite

Microcrystalline quartz (SiO₂), likely quartzite or silicified rock

Greenstone (likely chlorite- or epidote-rich metamorphic rock)

Greenstone; commonly metamorphosed basalt or dolerite, with chlorite, epidote, and actinolite

Weathered granite or granitic gneiss

Granite–gneiss aggregate, chiefly quartz, feldspar, and dark mica/amphibole

Dark slate (probable)

Slate, a fine-grained metamorphic rock composed mainly of mica-group minerals and quartz; exact identification is uncertain from the photograph.

Iron-stained quartz-rich rock, likely weathered quartzite

Quartzite (dominantly quartz, SiO₂), with iron-oxide minerals such as hematite/goethite

Iron-stained quartz-rich rock, likely quartzite or silicified breccia

Quartz (SiO₂), possibly quartzite with limonite/goethite iron oxides

Rounded quartz-rich pebble

Likely quartz arenite or quartzite pebble; exact identification is uncertain from the photograph

Rounded quartz-rich river pebble

Feldspathic quartz sandstone or quartzite pebble (exact identification requires testing)

Likely weathered sandstone or quartzite

Quartz-rich sandstone (SiO₂-dominant); possibly metamorphosed to quartzite

Quartzite with Iron Inclusions

Metamorphosed Quartz-Rich Sandstone (SiO2 with Fe2O3)

Rounded quartz-rich pebble, likely quartzite

Quartzite (microcrystalline quartz, SiO₂), possibly quartz-rich sandstone

Tumbled yellow-brown quartzite or jasper

Quartzite, predominantly microcrystalline quartz (SiO₂), possibly iron-stained jasper

Graphite-rich schist (probable)

Graphite schist; primarily graphite (C) with mica and quartz

Blue-gray layered sedimentary pebble

Likely micaceous shale or slate; exact identification requires testing

Likely quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂); if granular and recrystallized, quartzite

Quartz-rich iron-stained rock, likely quartzite or quartz vein material

Quartz (SiO₂), with iron oxides/hydroxides such as hematite and goethite

Banded iron formation (iron-rich quartzite)

BIF; quartz (SiO₂) with hematite/magnetite (Fe₂O₃/Fe₃O₄), possibly amphibole or mica

Polished gray stone, likely quartzite or river-worn granite

Tentatively quartzite (mostly microcrystalline SiO₂); exact identification is uncertain from the photograph

White quartz-rich rock, likely quartzite or silicified sediment

Quartzite (mostly quartz, SiO₂); possibly silicified limestone or chert

Quartz-rich rock, likely milky quartz

Quartz (silicon dioxide, SiO₂), possibly a quartzite fragment