Sedimentary Rock (Metamorphosed)

Likely serpentinized ultramafic rock (serpentinite)

Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with possible magnetite, chromite, and relict olivine/pyroxene

Likely iron-rich quartzite or ironstone pebble

Quartz-rich rock with iron-oxide staining; exact identification requires examination

Gray flagstone, likely slate

Slate, a fine-grained metamorphic rock composed mainly of quartz, mica, and chlorite

Likely weathered granite or granitic gneiss

Granite: quartz + feldspar + mica; possibly gneiss if the faint banding is structural

Rounded quartz-rich pebble

Likely quartzite or quartz-rich sandstone; predominantly SiO₂

Gneissic granite cobble

Granitic gneiss; quartz–feldspar–biotite assemblage

Weathered quartz-bearing rock, possibly quartzite or feldspathic sandstone

Quartzite (SiO₂-rich), with possible iron-oxide staining and feldspar/mica impurities

Quartz-rich rock, possibly iron-stained quartz or quartzite

Quartz (SiO₂), potentially quartzite with iron-oxide staining

Dark gray metamorphic rock, likely slate or phyllite

Slate/phyllite; commonly quartz, muscovite/illite, chlorite, and minor feldspar

Iron-stained quartz-rich rock, possibly quartzite or quartz vein

Quartz (SiO₂), likely with iron-oxide minerals such as limonite/goethite; exact host rock is uncertain from the photo

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

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

Weathered sandstone or iron-stained quartzite

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

Greenstone (likely metamorphosed basalt)

Metabasalt/greenstone; commonly composed of chlorite, actinolite, epidote, albite, and quartz

Likely granite or granitic gneiss

Coarse quartz–feldspar–mica rock; if gneissic, metamorphosed granitoid

Granite or granitic gneiss

Coarse quartz–feldspar–mica rock; possible gneissic variant

Likely serpentine-rich metamorphic rock

Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, or chrysotile), with possible magnetite and minor chlorite/talc

Likely quartz-bearing metamorphic pebble

Indeterminate; probable quartzite or quartz-rich gneiss with dark mica/amphibole

Banded greenstone or altered basalt

Chlorite–epidote amphibolite/greenstone; exact identification requires testing

Aventurine

Quartz (Aventurine variety)

Iron-stained quartz-rich rock, possibly jasper/quartzite

Quartz (SiO₂) with iron-oxide staining; likely ferruginous quartzite or jasper

Rounded greenish river pebble

Likely altered basalt or greenstone (metabasalt); exact identification requires testing

Quartz and Slate Pebbles

Silicon Dioxide (SiO2) and Metamorphosed Shale/Mudstone

Iron-stained quartzite (likely)

Quartzite, predominantly quartz (SiO₂), with iron-oxide staining and possible mica/feldspar

Weathered granite or granitic gneiss

Granite–gneiss, chiefly quartz, feldspar, and mica

Likely quartz-bearing rock (possibly milky quartz or quartzite)

Quartz, silicon dioxide (SiO₂); exact identification is limited by the small photograph

Quartzite with Hematite

Metamorphosed Quartz Sandstone (SiO2 with Fe2O3 inclusions)

Rounded greenstone cobble

Likely altered basalt/greenstone; commonly chlorite–actinolite–epidote rich

Quartzite (with Iron Staining)

Metamorphosed Sandstone (mainly SiO2 with Fe2O3/FeOOH impurities)

Milky quartz-rich rock (likely quartzite)

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

Iron-rich metamorphic rock, likely magnetite–hematite-bearing ironstone

Banded or massive iron formation (BIF), chiefly hematite (Fe₂O₃) and magnetite (Fe₃O₄), with quartz and possible iron silicates

Iron-stained quartz-bearing rock, possibly quartzite

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

Tumbled limestone or calcitic marble

Calcite-rich carbonate rock; primarily calcium carbonate (CaCO₃)

Weathered iron-rich metamorphic rock, likely schist or quartzite

Provisional identification: ferruginous quartzite or mica schist; composition likely quartz (SiO₂), iron oxides/hydroxides, and mica or clay minerals

Quartz-rich mica schist (probable)

Mica–quartz schist; mainly quartz (SiO₂) with muscovite/biotite mica and possibly feldspar

Iron-rich quartzite or weathered ironstone

Quartzite, chiefly SiO₂, with iron-oxide minerals such as hematite/goethite

Likely quartz-rich pebble (possibly weathered quartzite)

Quartzite; predominantly SiO₂ (identification tentative from photograph)

Milky quartz (quartzite possible)

Quartz, silicon dioxide (SiO₂)

Likely granite or granitic gneiss pebble

Granite: quartz + feldspar + mica; possibly gneiss if the minerals show layering

Rounded quartz-rich pebble, likely milky quartz or quartzite

Quartz (SiO₂); possibly quartzite, a metamorphosed quartz sandstone

Banded river pebble, likely quartzite or metamorphosed sandstone

Quartzite (quartz-rich metamorphic rock), possibly banded sandstone

Weathered chert or novaculite (flaked stone tool/fragment possible)

Microcrystalline quartz (SiO₂); likely chert, possibly Arkansas novaculite

Mica-rich schist (likely quartz-mica schist)

Quartz–mica schist; chiefly quartz with muscovite and/or biotite