Organic (Paper And Cellulose)

Tumbled orbicular granite (likely orbicular diorite)

Orbicular granitoid; chiefly quartz, feldspar, and dark amphibole/biotite minerals

Agate Geode / Thunderegg

Chalcedony (cryptocrystalline variety of Quartz), SiO2

Muscovite Mica

Muscovite - KAl2(AlSi3O10)(F,OH)2

Anthracite coal

Anthracite; predominantly carbon (C), with minor mineral ash

Banded Sandstone

Arenite (with iron oxide banding)

Rounded dark river pebble

Likely basalt or fine-grained andesite; exact identification requires testing

Marble

Recrystallized Calcite (CaCO3)

Banded Iron Formation (BIF) / Red Jasper with Hematite

Ferruginous Chert (primarily Quartz [SiO2] and Hematite [Fe2O3])

Carrara Marble

Metamorphosed Limestone (principally Calcium Carbonate, CaCO3)

Porphyritic Basalt

Basalt with plagioclase phenocrysts

Polished/tumbled stones, likely quartz varieties

Likely quartz (SiO₂), with the left specimen possibly rose quartz or orange calcite; exact identification is uncertain from the image

Blue agate slice with quartz crystal cavity

Chalcedony (microcrystalline SiO₂) with quartz (SiO₂)

Pyrite

Iron Disulfide (FeS2)

Calcite

Calcium Carbonate (CaCO3)

Pyrite

Iron Sulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Gowganda Tillite (Puddingstone)

Glacial Tillite (Diamictite) with Jasper inclusions

Polished fossiliferous agate

Chalcedony (microcrystalline SiO₂) containing fossil fragments, likely an agatized limestone or stromatolite

Banded Gneiss

Gneiss (Metamorphic high-grade, predominantly SiO2, Al2O3, K2O, Na2O)

Dyed tumbled stone, likely chalcedony or quartz

Microcrystalline quartz (SiO₂), probably dyed magenta

Tumbled blue-gray stone, likely quartzite or chalcedony

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

Limestone

Calcium Carbonate (CaCO3)

Limestone

Calcareous sedimentary rock (CaCO3)

Polished banded agate (probable)

Microcrystalline quartz/chalcedony, SiO₂, with iron-oxide inclusions

Polished dark agate or jasper pebble

Microcrystalline quartz (SiO₂), likely chalcedony with iron-oxide inclusions

Polished gray stone, likely quartzite or river-worn granite

Tentatively quartzite (mostly microcrystalline SiO₂); exact identification is uncertain from the photograph

Polished brown pebble

Likely altered basalt or mafic volcanic rock; exact identification is uncertain from the photograph

Polished fossiliferous agate

Chalcedony (microcrystalline SiO₂), likely containing fossil coral or stromatoporoid structures

Rounded granite pebble

Granite; chiefly quartz, feldspar, and mica

Milky quartz pebble

Quartz, silicon dioxide (SiO₂)

Quartz geode (likely chalcedony-lined geode)

Silica geode: microcrystalline quartz/chalcedony with drusy quartz (SiO₂), possibly iron-oxide staining

Polished pink chalcedony (likely pink agate/geode)

Microcrystalline quartz, SiO₂; chalcedony with iron-bearing inclusions and possible druzy quartz

Slag Glass (Cullet)

Amorphous Silica (man-made), primarily SiO2 with trace metal oxides

Limestone

Calcium Carbonate (CaCO3)

Orange Quartzite (or Iron-Stained Quartz)

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

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Marble

Recrystallized Calcite (CaCO3)

Honey Calcite

Calcite (Calcium Carbonate - CaCO3)

Agate (specifically Lace Agate or Banded Agate)

Silicon Dioxide (SiO2)

Polished blue agate geode slice

Chalcedony (microcrystalline quartz), SiO₂, with possible quartz/drusy lining and iron-oxide coloration

Rounded dark river cobble, likely basalt

Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase and pyroxene, commonly with olivine

Limestone (Chalk / Calcite Rock)

Calcium Carbonate (CaCO3)