Sedimentary Rock (Metamorphosed)

Biotite-bearing gneiss or schist

Quartz–feldspar–mica metamorphic rock, likely mica schist/gneiss

Weathered quartz-rich rock, likely chert or quartzite

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

Gneiss pebble

Biotite–quartz–feldspar gneiss, possibly granitic gneiss

Veined Quartzite Pebble (Heart-Shaped)

Metamorphosed quartz-rich sandstone with quartz veins

Iron-rich quartzite or ironstone fragment

Quartzite dominated by quartz (SiO₂), with iron oxides such as hematite/goethite

Quartz-rich rock, possibly quartzite

Quartzite (dominantly quartz, SiO₂); identification is provisional from the photo

Quartz-bearing metamorphic rock, likely quartzite or hornfels

Quartz (SiO₂) in a fine-grained silicate matrix; exact rock identification requires testing

Red jasper-bearing rock

Jasper (microcrystalline quartz, SiO₂), likely hematite-rich metachert or ironstone

Granite or granitic gneiss pebble

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

Dark gray metamorphic cobble, likely slate or phyllite

Foliated metapelite; possibly slate/phyllite composed mainly of quartz, mica, and chlorite

Weathered, biotite-bearing granite or granitic gneiss

Quartz–feldspar–biotite rock; likely granite (compositionally, quartz + K-feldspar/plagioclase + biotite), possibly weakly foliated gneiss

Weathered quartz-rich rock, possibly quartzite or chert

Quartz (SiO₂), likely in a quartzite matrix; exact identification is uncertain from the image

Tan quartz-rich rock, likely sandstone or weathered quartzite

Quartz sandstone; primarily SiO₂ with possible feldspar and iron-oxide cement

Weathered quartz-rich pebble, possibly sandstone

Indeterminate quartz-rich clastic rock; likely ferruginous sandstone or weathered quartzite

Iron-stained metamorphic rock, likely schist or quartzite

Quartz–mica–iron oxide rock; probable muscovite/biotite schist or ferruginous quartzite

Dark gray foliated metamorphic rock, likely slate or phyllite

Slate/phyllite; chiefly quartz, mica, and chlorite

Kyanite-rich schist (probable)

Kyanite-bearing quartz–mica schist; kyanite, Al₂SiO₅

Gneiss (Metamorphosed Pebble)

Gneiss with Quartz/Feldspar banding

Rounded quartz-rich river pebble

Likely quartzite or silicified sandstone; predominantly microcrystalline quartz (SiO₂), possibly with feldspar and iron-oxide staining

Mica-rich metamorphic rock, likely schist

Muscovite- or biotite-bearing schist; composition commonly quartz + mica ± feldspar

Weathered granite or granitic gneiss boulder

Granite–gneiss; chiefly quartz, feldspar, and mica

Sulfur-bearing iron ore, likely pyrite-rich gossan

Pyrite (FeS₂) with iron oxides/hydroxides and dark host rock

Fossiliferous shale or slate with plant impressions

Carbonaceous mudstone/shale; possible fossil plant material (often fern-like impressions)

Polished jasper–quartzite river pebble

Silicified metasedimentary rock, chiefly microcrystalline quartz (SiO₂) with iron-oxide staining

Unakite

Unakite (Metamorphosed granite)

Quartz-veined metamorphic cobble

Likely quartzite or quartz-rich metasedimentary rock; veins predominantly quartz (SiO₂)

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, possibly granitic gneiss

Likely slate or fine-grained metamorphic stone with quartz vein

Slate–phyllite, composed mainly of quartz, mica, and chlorite; the white vein is likely quartz

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

Tentative: quartz arenite (sandstone) or quartzite; chiefly SiO₂

Graphite-rich metamorphic rock (likely graphite schist)

Graphite schist; predominantly graphitic carbon (C) with mica and quartz

Weathered granite or granitic gneiss

Quartz–feldspar–mica granitic rock; possibly weakly foliated gneiss

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Rounded quartz-veined pebble

Likely quartz-veined metamorphic rock; exact host rock is indeterminate from the image

Rounded reddish-brown pebble

Likely ferruginous sandstone or iron-rich quartzite; exact identification requires a fresh surface and tests

Quartz-rich rock fragment, possibly granite or quartzite

Indeterminate quartz-bearing silicate rock; likely quartz (SiO₂) with feldspar and/or mica

Weathered quartz-bearing rock, possibly iron-stained quartzite

Quartzite (mostly SiO₂), tentatively identified

Marble

Recrystallized Calcite (CaCO3) or Dolomite (CaMg(CO3)2)

Fine-grained gray stone, possibly slate

Slate (fine-grained metamorphosed mudstone); identification is uncertain from the image

Anthracite coal

Anthracite; predominantly carbon (C), with minor mineral impurities

Quartzite with Milky Quartz Vein

Metamorphosed Quartz-rich Rock (SiO2)

Unakite

Unakite (metamorphosed granite)

Weathered quartz-rich rock, likely sandstone or quartzite

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