Sedimentary Rock (Metamorphosed)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Rounded brown pebble, likely quartz-rich sandstone or weathered quartzite

Indeterminate; probable quartz (SiO₂)-rich sandstone/quartzite with iron-oxide staining

Quartzite River Rock

Metamorphosed Quartz-rich Sandstone (SiO2)

Eclogite garnet in matrix

Eclogite (Garnet-Omphacite rock)

Quartzite Pebble

Metamorphosed Quartz-rich Sandstone (SiO2)

Light-colored granite or granitic gneiss

Granite; primarily quartz (SiO₂), feldspar, and minor mica, possibly with gneissic fabric

Veined quartz-bearing metamorphic rock

Likely quartzite or siliceous schist with iron-oxide staining

Quartzite (Yellow/Tan Quartz Cobble)

Metamorphosed Quartz Sandstone (SiO2)

White Marble

Metamorphosed Limestone (principally CaCO3)

Argillite (with Barnacles)

Argillite (metamorphosed mudstone/shale)

Tumbled quartz-rich stone, likely milky quartz

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

Rounded quartz-rich cobble

Likely quartzite or siliceous sandstone; predominantly microcrystalline SiO₂ with possible feldspar and iron-oxide staining

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Serpentine-rich altered rock (likely serpentinite)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, talc, or chlorite

Weathered igneous rock, likely granite or granitic gneiss

Quartz–feldspar–mica aggregate; exact identification requires a fresh surface or testing

Blue Quartzite (Blue Aventurine)

Silicon Dioxide (SiO2) with inclusions of Dumortierite or Magnesio-riebbeckite

Quartz / Quartzite

Silicon Dioxide (SiO2)

Greenstone / Greenschist

Metamorphosed mafic igneous rock (Greenschist facies)

Greenstone Celt (Polished Stone Axe)

Metamorphosed mafic rock (often Basalt or Diabase)

Rounded gray limestone pebble with a calcite vein

Calcitic limestone, composed predominantly of calcite (CaCO₃), locally cut by a white calcite vein

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Rounded gray-green pebble, likely basalt or fine-grained metamorphic rock

Probable basalt (plagioclase–pyroxene–iron oxide aggregate); exact identification requires testing

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Greenstone / Epidosite

Epidosite (primary minerals: Epidote and Quartz)

Greenstone Porphyry

Altered Porphyritic Andesite/Basalt

River Cobble (likely Metasedimentary or Basalt)

Metamorphosed Siltstone or Altered Fine-grained Igneous Rock

Iron-rich quartzite or limonite-bearing rock

Quartzite (SiO₂) with iron oxides/hydroxides, chiefly hematite and goethite

Tiger iron slab (likely polished banded iron formation)

Banded iron formation (BIF), chiefly hematite/magnetite, quartz, and iron-rich amphibole or jasper

Garnet amphibolite / Metamorphic Rock

Garnet Amphibolite (Hornblende - Almandine schist/gneiss)

Marble

Metamorphosed Limestone (principally CaCO3)

Quartzite

Quartzite (primarily SiO2)

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Gray metamorphic rock, likely slate or phyllite

Fine-grained foliated rock, probably quartz–mica slate/phyllite

Water-worn green pebble

Likely altered basalt or greenstone; precise identification requires testing

Quartzite

Metamorphosed Quartz Sandstone (primarily SiO2)

Weathered quartz-rich river cobble, possibly quartzite

Quartzite (mostly microcrystalline SiO₂), tentatively identified

Quartzite with Iron Inclusions

Metamorphosed Quartz-rich Rock (SiO2 with Fe2O3)

Shatter Cone

Impactite (Shatter Cone texture)

Likely galena-bearing metamorphic sulfide ore

Galena (PbS), possibly with pyrite and/or sphalerite in a schistose host