Unknown (Likely Sedimentary Or Metamorphic)

Pink-and-white banded quartzite or jasper

Quartzite, primarily microcrystalline SiO₂, possibly iron-stained quartz/chalcedony

Gray metamorphic rock, likely gneiss or schist

Quartz–feldspar–mica metamorphic rock; exact identification requires a fresh surface and tests

Likely tumbled quartz or chalcedony fragment

Quartz (SiO₂), possibly microcrystalline chalcedony

Banded metamorphic rock, likely gneiss

Banded quartzofeldspathic gneiss (probable paragneiss or orthogneiss)

Polished garnet-bearing metamorphic rock

Likely garnet mica schist or garnet-bearing gneiss; garnet is commonly almandine, Fe₃Al₂(SiO₄)₃

Pyritic Gneiss

Metamorphic Gneiss with Pyrite inclusions

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Metallic sulfide-bearing metamorphic rock

Likely graphitic schist or sulfide-rich schist, with possible pyrite/arsenopyrite and mica

Iron-stained quartz vein rock

Quartz-rich vein material, predominantly SiO₂, with iron oxyhydroxides (goethite/limonite) and likely sulfide alteration

Weathered gray metamorphic rock, likely slate or phyllite

Foliated metapelite; composition commonly quartz, mica, and chlorite

Dark metamorphic rock, likely schist or phyllite

Quartz–mica schist/phyllite; chiefly quartz, mica, and feldspar

Quartz-bearing dark rock, possibly hornfels or basalt

Probable quartz–feldspar rock; exact identification requires testing

Rounded quartz-rich river pebbles

Alluvial gravel; commonly quartzite, chert, and quartz-bearing sandstone fragments

Weathered metallic sulfide ore, likely pyrite-bearing rock

Pyrite (FeS₂), possibly in a quartz–iron-oxide host

Milky quartz-rich rock

Quartz, SiO₂; possibly quartzite or massive vein quartz

Quartz (Grain)

Silicon Dioxide (SiO2)

Pyrite (likely)

Iron disulfide, FeS₂; commonly called fool’s gold

Baked-clay ceramic fragment (likely brick or pottery)

Fired clay, primarily aluminosilicate minerals; not a natural rock

Banded gneiss (likely amphibolite-bearing gneiss)

Gneiss; quartz–feldspar–mica/amphibole aggregate

Tumbled blue-gray stone, likely quartzite or chalcedony

Quartz-rich rock; predominantly microcrystalline or granular SiO₂, identification uncertain from image

Gneiss (Green Gneiss)

Gneiss (High-grade Regional Metamorphic Rock)

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Weathered gray metamorphic rock, likely gneiss or schist

Probable quartz–feldspar–mica gneiss/schist; exact identification requires a fresh surface and tests

Polished green banded stone, likely serpentine or altered greenstone

Probable serpentinite/greenstone; commonly dominated by serpentine-group minerals, chlorite, epidote, or actinolite

Weathered sandstone fragment

Quartz-rich sandstone (compositionally uncertain)

Quartz-bearing metamorphic rock, possibly quartzite or hornfels

Mostly quartz (SiO₂), with probable iron-oxide and dark silicate minerals

Weathered limestone or calcareous concretion

Calcite-rich limestone; predominantly calcium carbonate (CaCO₃)

Tumbled brown quartzite or jasper

Quartzite (mostly SiO₂), possibly iron-rich jasper (microcrystalline quartz)

Fossilized marine shell fragment

Likely a bivalve or gastropod shell preserved as calcite (CaCO₃)

Pale quartz-rich stone, possibly calcite

Likely quartz (SiO₂) or calcite (CaCO₃); image resolution prevents confident separation

Smoky Quartz and Biotite Schist

Quartz-Biotite Schist (SiO2 + K(Mg,Fe)3AlSi3O10(F,OH)2)

Biotite-rich schist (likely mica schist)

Mica schist; predominantly quartz, biotite mica, and feldspar

Olivine-rich peridotite / olivine crystal fragment

Olivine, typically (Mg,Fe)₂SiO₄; possibly peridotite if the specimen is rock rather than a single crystal

Fossil-bearing fine-grained sedimentary rock

Likely fossiliferous mudstone or shale; visible feature may be a plant fragment, trace fossil, or mineral vein

Banded metamorphic rock, likely gneiss or amphibolite

Composition uncertain; probable quartz–feldspar–amphibole assemblage

Banded gray stone, likely slate or fine-grained metamorphic rock

Probably slate or phyllite; composition commonly mica, quartz, and clay-derived minerals

Polished bumblebee jasper

Calcite–orpiment/realgar-rich silicified volcanic rock (commercially called bumblebee jasper)

Mica-rich metamorphic rock, likely schist

Muscovite–biotite schist, possibly phyllite; composition dominated by mica and quartz

Argillite (with Barnacles)

Argillite (metamorphosed mudstone/shale)

Rounded river cobbles, likely weathered sandstone/mudstone and quartz-rich rock

Uncertain from photograph; probable lithologies include quartz sandstone, siltstone/mudstone, and locally altered volcanic or metamorphic clasts

Tumbled quartz pebble, possibly citrine or pale smoky quartz

Quartz (SiO₂), likely microcrystalline/tumbled material

Jasper

Silicon dioxide (SiO2)