Metamorphic Or Sedimentary Depending On Local Grade

Lichen-covered graywacke or granitic glacial cobble

Indeterminate; likely quartz–feldspar–mica rock, possibly weathered granite or granodiorite

Banded gneiss

Gneiss; typically quartz–feldspar–biotite ± amphibole

Likely slate fragment

Slate; predominantly fine-grained mica/clay minerals and quartz

Conglomerate

Clast-supported polymictic conglomerate; rounded quartz and other rock fragments in a dark matrix

Sandstone (Quartz Sandstone)

Arenite (SiO2 based)

Quartz-rich mica schist

Muscovite–quartz schist, with possible feldspar and iron-oxide staining

Polygenetic Conglomerate (Puddingstone)

Conglomerate (SiO2 matrix with mixed clasts)

Fossilized Bone Fragment

Permineralized Skeletal Element (Likely Vertebrate)

Anthracite Coal

Anthracite

Gneiss

Gneiss (High-grade metamorphic rock)

Crushed Stone (Gravel/Aggregates)

Crushed rock aggregate (varied composition including Granite, Limestone, and Quartz)

Banded gneiss

Orthogneiss or paragneiss, chiefly quartz–feldspar–mica

Sandstone (Quartz-rich)

Arenite (composed primarily of SiO2)

Chert (or Ironstone Nodule)

Silicon Dioxide (SiO2) or Limonite-stained Cryptocrystalline Quartz

Chert Nodule (Commonly known as Flint or River Rock)

Silicon Dioxide (SiO2)

Limestone (Concretionary or Tufa)

Calcium Carbonate (CaCO3)

Charoite

Charoite (Hydrated potassium sodium calcium barium strontium silicate hydroxyfluoride)

Greenstone / Serpentinite Pebble

Serpentinite (Hydrated Magnesium Silicate, Mg3Si2O5(OH)4)

Quartzite (Lithic Artifact)

Quartzite (SiO2)

Calcite with iron staining

Calcium Carbonate (CaCO3)

Greywacke (River Pebble)

Greywacke sandstone with quartz veining

Fossiliferous Sedimentary Rock (Coquina/Limestone)

Fossiliferous Calcarenite / Bioclastic Limestone

Garnet-Mica Schist

Garnetiferous Porphyroblastic Schist

Chert or siliceous limestone fragments

Microcrystalline quartz (chert) and/or calcarenite; exact identification is uncertain from the photograph

Fulgurite

Fulgurite (Lechatelierite), amorphous SiO2

Chert (Quartz Variety)

Microcrystalline Silica (SiO2)

Sandstone (Nut-stone / Cup-stone artifact)

Quartz Arenite / Worked Sedimentary Rock

Gneiss

Gneiss (High-grade metamorphic rock)

Kyanite (in Schist Matrix)

Kyanite (Al2SiO5)

Mica Schist

Mica Schist (contains muscovite/biotite, quartz, plagioclase)

Gneiss with Quartz Veining

Gneiss (High-grade Metamorphic Rock)

Chert (Jasper variety)

Microcrystalline quartz (SiO2)

Foliated metamorphic rock, likely schist

Mica schist or chlorite schist; composition commonly quartz + mica/chlorite ± feldspar

Fossil-bearing sandstone or mudstone

Indeterminate sedimentary matrix with a possible bivalve or shell fossil

Weathered quartz-rich rock, likely quartzite or quartz vein

Quartzite; predominantly quartz (SiO₂), possibly iron-oxide stained

Gneiss

High-grade foliated metamorphic rock

Slate

Metamorphic Mudstone / Shale

Blue quartzite (likely)

Quartzite, composed predominantly of quartz (SiO₂); blue coloration may come from fine mineral inclusions

Labradorite (rough specimen)

Labradorite, a plagioclase feldspar in the labradorite–bytownite series; approximately (Ca,Na)(Al,Si)₄O₈

Chert

Silicon dioxide (SiO2)

Weathered quartz-rich rock (likely quartzite)

Quartzite, composed predominantly of quartz (SiO₂); identification is tentative from the photo

Fossilized Bone Fragment

Permineralized Vertebrate Bone (Hydrox yapatite replaced by Silica or Calcite)