Organic (Paper And Cellulose)

Polished agate/geode slice

Microcrystalline quartz (chalcedony), mainly SiO₂, with possible calcite or quartz druse

Muscovite Mica (Golden/Yellow variety)

KAl2(AlSi3O10)(F,OH)2

Sandstone (with biological crust)

Arenite (SiO2 based)

Sandstone (likely Quartzose)

Sandstone (Principally SiO2)

Clear Quartz (Facet Cut / Polished)

Silicon Dioxide (SiO2)

Muscovite Mica (in Quartz matrix)

Potassium aluminum silicate hydroxide fluoride (KAl2(AlSi3O10)(F,OH)2)

Graphitic schist (likely carbonaceous slate)

Graphite-bearing pelitic schist; mainly quartz, mica, feldspar, and graphite

Muscovite Schist with Quartz

Muscovite (KAl2(AlSi3O10)(OH)2) in Quartz Matrix

Limestone

Calcium Carbonate (CaCO3)

Tumbled amber-colored chalcedony

Chalcedony (microcrystalline quartz, SiO₂), possibly yellow jasper or resinous amber-colored agate

Likely graphite-rich schist or graphite-bearing metamorphic rock

Graphite (C) in a mica/quartz-rich matrix; exact rock name requires testing

Polished jasper pebble

Jasper, microcrystalline quartz (SiO₂) with iron-oxide and clay inclusions

Banded Agate

Cryptocrystalline Quartz (SiO2)

Dyed and polished agate geode slice

Banded chalcedony, SiO₂, with a quartz-lined cavity

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Sandstone (Pet Rock)

Clastic sedimentary rock (primarily SiO2)

Polished banded agate (likely sardonyx)

Cryptocrystalline chalcedony, SiO₂; reddish bands are iron-stained layers

Limestone

Calcite rock (CaCO3)

Banded iron formation (specimen, possibly hematite–jasper)

Banded iron formation; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and silica (chert/quartz), with possible limonite/goethite staining

Garnet in Schist (Polished Tower)

Almandine Garnet (Fe3Al2(SiO4)3) in Mica Schist

Tumbled greenish chalcedony or serpentine pebble

Likely microcrystalline quartz (chalcedony, SiO₂) or serpentine-group mineral; exact identification requires testing

Tumbled banded agate

Chalcedony (microcrystalline quartz), SiO₂

Tumbled pegmatitic rock, likely amazonite-bearing granite

Granite/pegmatite composed mainly of quartz, feldspar, and mica; blue-green area may be microcline (amazonite)

Tumbled banded agate

Agate, microcrystalline quartz (SiO₂), commonly chalcedony with iron-oxide inclusions

Quartz geode slice

Microcrystalline and crystalline quartz, silicon dioxide (SiO₂)

Tumbled orbicular granite or granitic gneiss

Granite, chiefly quartz–feldspar–biotite/amphibole; exact variety uncertain from the image

Banded Agate (specifically Sardonyx or Carnelian Agate)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Polished chalcedony (likely sagenite or included agate)

Microcrystalline quartz, SiO₂, with iron-oxide and possibly rutile/goethite inclusions

Polished fossiliferous limestone, possibly ammonite-bearing

Calcite-rich limestone (CaCO₃), with visible fossil or shell fragments

Polished agate geode slice

Quartz (SiO₂), chiefly chalcedony with drusy crystalline quartz; likely an agate geode

Fossil Coral (Petoskey Stone / Rugose Coral)

Hexagonaria percarinata (or similar fossilized rugose/tabulate coral)

Black polished/tumbled stone, likely basalt or black jasper

Most likely fine-grained basalt (plagioclase and pyroxene); appearance can also match microcrystalline quartz (black jasper)

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Dyed and polished agate pebble

Microcrystalline quartz (SiO₂), likely chalcedony/agate with blue dye

Red Sandstone

Arenite (Ferruginous Sandstone)

Desert rose

Gypsum (selenite), CaSO₄·2H₂O, commonly forming rosette aggregates

Glauconite Siltstone

Glauconitic siltstone / K(Fe,Al,Mg)2[(Si,Al)4O10](OH)2

Sandstone (Ferruginous)

Arenite with Iron Oxide (Limonite/Hematite) coating

Slate

Foliated metamorphic rock

Banded Agate

Silicon Dioxide (SiO2)

Slate

Slate (Foliated metamorphic rock consisting mainly of quartz and muscovite or illite)