Synthetic Or Natural Fiber

Banded Agate

Chalcedony (Cryptocrystalline Silica) SiO2

Carnelian Agate

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Red Jasper with Quartz Veining

Jasper (Silicon Dioxide, SiO2)

Ruby (Corundum)

Corundum (Aluminum Oxide) with chromium trace elements, Al2O3

Tumbled pale green quartz (likely aventurine or common quartz)

Quartz, silicon dioxide (SiO₂); green color may result from fuchsite or chlorite inclusions

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Tumbled milky quartz

Quartz, silicon dioxide (SiO₂)

Tumbled yellow chalcedony (likely citrine or yellow jasper)

Cryptocrystalline quartz, SiO₂; exact identification requires testing

Yellow Quartz (Citrine/Iron-Stained Quartz)

Silicon Dioxide (SiO2)

Limestone (Buff/Tan)

Calcium Carbonate (CaCO3)

Yellow tumbled mineral, likely citrine or yellow quartz

Quartz (SiO₂), possibly iron-colored citrine; exact identification requires testing

Weathered limestone

Calcite-rich limestone (CaCO₃), possibly fossiliferous

Brown Quartz Pebble

Silicon Dioxide (SiO2)

Rounded river pebble, likely sandstone or weathered quartzite

Indeterminate lithic clast; probable quartz-rich sandstone (SiO₂-dominant)

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Iron Ore / Hematite / Ironstone Nodule

Hematite / Goethite (Fe2O3 / FeO(OH))

Tumbled dark purple quartz, likely amethyst

Quartz (SiO₂), purple variety amethyst; possibly iron-bearing quartz with surface sparkle

Tumbled yellow quartz (likely citrine or iron-stained quartz)

Quartz, silicon dioxide (SiO₂), colored yellow by iron impurities; possibly heat-treated amethyst

Yellow Quartz (Citrine or Iron-Stained Quartz)

Silicon Dioxide (SiO2)

Tumbled greenstone, likely serpentine

Serpentinite/serpentine-group minerals, chiefly Mg₃Si₂O₅(OH)₄; possibly chlorite-bearing greenstone

Yellow Quartz (Golden Quartz)

Silicon Dioxide (SiO2)

Quartz (Yellow / Citrine Quartz Pebble)

Silicon Dioxide (SiO2)

Quartz (Citrine or Iron-Stained)

Silicon Dioxide (SiO2)

Yellow Quartz / Citrine Quartz

Silicon Dioxide (SiO2)

Citrine or Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Orange Quartzite (or Quartz River Pebble)

Silicon Dioxide (SiO2) - Quartzite

Tumbled pink feldspar-rich granite

Granite, composed mainly of quartz, potassium feldspar, and plagioclase, with minor dark minerals

Tumbled green glassy mineral, possibly aventurine or fluorite

Uncertain; likely quartz variety (aventurine quartz, SiO₂) or green fluorite (CaF₂)

Polished basalt pebble

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

Polished black pebble, likely basalt

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

Polished dendritic agate or jasper pebble

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

Tumbled white quartz pebble

Quartz (silicon dioxide, SiO₂)

Quartz (Citrine or Iron-Stained)

Silicon Dioxide (SiO2)

Opalite (likely imitation opal glass)

Man-made opalescent glass; not a natural mineral (often sold as opalite)

Tumbled pale-green stone, likely serpentine or green aventurine

Probably serpentine-group minerals, chiefly lizardite/antigorite; exact identification requires testing

Quartz (Citrine / Golden Quartz)

Silicon Dioxide (SiO2)

Yellow Quartz (Citrine or Iron-stained Quartz)

Silicon Dioxide (SiO2)

Rough Quartz (var. Citrine or Yellow Quartz)

Silicon Dioxide (SiO2)

Tumbled chalcedony (likely agate)

Microcrystalline quartz, SiO₂; chalcedony with possible agate banding

Polished black-and-white banded stone, likely a dendritic agate or marble

Uncertain; probable calcite marble or chalcedony agate with white mineral veining

Likely weathered volcanic rock (possibly basalt)

Basalt, a fine-grained mafic igneous rock; exact identification is uncertain from the photograph

Weathered, porous limestone (probable fossiliferous limestone)

Calcite-rich limestone; predominantly CaCO₃