Mineralogical

Tumbled chert or flint pebble

Microcrystalline quartz (SiO₂), likely chert

Granite Cobble

Plutonic Granite

Fossilized bivalve shell

Fossil mollusk, likely an oyster or similar bivalve; original shell composed of calcium carbonate (aragonite/calcite)

Polished brown flint/chert nodule

Microcrystalline quartz (SiO₂), commonly called flint or chert

Weathered iron-rich volcanic rock

Likely altered basalt or andesite with iron-oxide staining

Sandstone Concretion

Ferruginous Sandstone Concretion (Primarily SiO2 with Iron Oxide cement)

Diorite

Diorite (an intermediate intrusive igneous rock)

Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Reddish-brown crystalline rock, possibly weathered granite or garnet-bearing schist

Indeterminate; likely quartz–feldspar–mica rock with iron oxides, potentially garnet-bearing

Greenstone / River Jadeite pebble

Metavolcanic rock / Chlorite or Actinolite-rich schist

Graphite-bearing quartz-mica schist

Graphite-rich quartz–mica schist; primarily quartz (SiO₂), muscovite/biotite, and graphite (C)

Blue glass-like tumbled specimen

Most likely cobalt-blue slag glass or manufactured glass; not confidently identifiable as a natural mineral from the image

Tumbled serpentine-rich altered rock

Serpentinite, likely antigorite/lizardite with accessory carbonate, quartz, or iron oxides

Likely graphite-rich schist (possibly galena-bearing metamorphic rock)

Graphite schist; chiefly quartz–mica with graphite (identification uncertain from photograph)

Unakite (likely)

Epidote–pink feldspar–quartz rock; commonly termed unakite

Granite Pegmatite

Granitic Pegmatite (composition: SiO2 with KAlSi3O8)

Tumbled mica-rich stone, likely muscovite schist

Muscovite-bearing quartz schist; chiefly muscovite mica, quartz, and possibly feldspar

Dark volcanic rock, likely basalt

Basalt (fine-grained mafic igneous rock; commonly plagioclase, clinopyroxene, and olivine)

Rounded basalt pebble

Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase feldspar and pyroxene, with possible olivine

Tumbled sodalite (probable)

Sodalite, Na₈(Al₆Si₆O₂₄)Cl₂; possibly blue-dyed jasper or lapis lazuli

Weathered rhyolitic tuff or altered volcanic rock

Felsic volcanic tuff, likely devitrified or hydrothermally altered

Granite

Granite (Felsic Plutonic Rock)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Pale-green schist fragment

Chlorite–sericite schist, possibly containing epidote or actinolite

Limonite with Quartz

FeO(OH)·nH2O (Limonite) with SiO2 (Quartz)

Polished greenstone pebble (likely epidote-bearing stone)

Epidote–chlorite amphibolite or altered basalt; composition likely epidote, chlorite, amphibole/pyroxene, and iron oxides

Scoria (vesicular volcanic rock)

Basaltic to andesitic scoria; chiefly plagioclase, pyroxene, and volcanic glass

Iron-rich metamorphic rock, likely specular hematite-bearing schist

Hematite–quartz–mica schist (tentative)

Small quartz-rich stone, possibly granite fragment

Indeterminate; likely quartz (SiO₂) with feldspar and/or mica

Serpentinite (probable)

Serpentinite; chiefly serpentine-group minerals, Mg3Si2O5(OH)4, with possible magnetite, chromite, and carbonate

Serpentinite

Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite and minor chromite

Polished serpentine-rich stone

Serpentinite, primarily serpentine-group minerals (antigorite, lizardite, or chrysotile)

Blue sodalite-bearing rock (likely sodalite rough)

Sodalite, Na₈(Al₆Si₆O₂₄)Cl₂, possibly in syenite or lapis-lazuli-like matrix

Flint or chert flake

Microcrystalline quartz (SiO₂), commonly chert/flint

Eclogite

Eclogite (Omphacite + Almandine-Pyrope Garnet)

Quartz Pebble

Silicon Dioxide (SiO2)

Polished dark green stone (likely serpentine or greenstone)

Serpentine-group mineral aggregate, commonly antigorite/lizardite; identification is uncertain from the image

Tumbled greenstone/serpentinite pebble

Serpentinite, chiefly antigorite/lizardite Mg₃Si₂O₅(OH)₄; identification is visual and uncertain

Polished blue-green feldspar-rich slab, likely amazonite

Amazonite, green microcline (KAlSi₃O₈), possibly with quartz and albite inclusions

Cat's Eye Moonstone (Feldspar)

Orthoclase (KAlSi3O8) with Albite (NaAlSi3O8) inclusions

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, potentially altered granite

Tumbled Slate or Basalt Pebble

Metamorphic fine-grained rock / Slate or Phyllite