Mineral With Artificial Coating

Limonite (Iron Ore)

Limonite (unstructured hydrated iron(III) oxide-hydroxides, often FeO(OH)·nH2O)

Polished blue lace agate slice

Chalcedony (microcrystalline quartz), SiO₂, commonly with blue-gray banding and a druzy quartz center

Pink Banded Agate (Dyed)

Chalcedony (cryptocrystalline silica), chemical formula SiO2

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily Quartz, SiO2)

Quartz with Epidote

Silicon dioxide (SiO2) with Calcium aluminum iron silicate (Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH))

Tumbled blue-green stone, likely chrysocolla-bearing material

Chrysocolla, hydrated copper phyllosilicate: approximately (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O; identification is provisional from the photograph

Red sandstone

Iron-oxide-cemented quartz-rich sandstone (ferruginous sandstone)

Quartz Druzy on Matrix

SiO2

Quartz Druzy on Geode Fragment

Silicon Dioxide (SiO2)

Weathered metamorphic rock, likely schist or slate

Foliated pelitic metamorphic rock; commonly muscovite–chlorite schist or phyllite

Weathered granitoid rock

Granite or granitic gneiss; chiefly quartz, feldspar, and mica

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Dyed Agate

Silicon dioxide, SiO2

Tumbled quartz-rich stone, possibly druzy quartz or chalcedony

Quartz/chalcedony (SiO₂); exact identification is uncertain from the photograph

Blue Lace Agate

Silicon Dioxide (SiO2) - Variety of Chalcedony

Kaolinite (China Clay / Chalky Claystone)

Al2Si2O5(OH)4

Banded Agate (Dyed / Polished)

Microcrystalline Quartz (SiO2)

Dyed Agate Geode (Pink/Magenta)

Silicon Dioxide (SiO2) - variety of Chalcedony/Quartz

Iron-stained Quartz

Silicon Dioxide (SiO2) with Iron Oxide (Limonite/Goethite) inclusions

Manganese Oxide Crust on Limestone

Manganese Oxides (e.g., Pyrolusite MnO2 or Romanechite) on CaCO3

Red chalcedony (likely dyed or heat-treated)

Microcrystalline quartz, SiO₂; possibly red agate/carnelian

Dyed Quartzite (Pink/Magenta)

Silicon Dioxide (SiO2) - Artificially Colored Quartzite

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Polished labradorite cabochon

Labradorite, CaAl₂Si₂O₈–NaAlSi₃O₈ (feldspar solid solution)

Dyed Agate

Chalcedony (Silicon Dioxide, SiO2)

Fossilized Shark Tooth

Carcharocles sp. (likely Lemon or Sand Tiger)

Weathered iron-rich rock (likely ironstone or limonite-bearing concretion)

Goethite–hematite–limonite mixture, commonly written FeO(OH) ± Fe₂O₃

Dyed blue-purple tumbled stone, likely quartz or calcite

Uncertain; commonly dyed quartzite/chalcedony (SiO₂) or calcite (CaCO₃)

Red Sandstone

Arenite (Ferruginous Sandstone)

Celadonite in Basalt (Green Earth)

Celadonite (K(Mg,Fe2+)(Fe3+,Al)Si4O10(OH)2)

Dyed Blue Agate

Chalcedony (Silicon Dioxide / SiO2)

Likely native metallic mineral specimen

Uncertain from photograph; possibly pyrite (FeS₂) or a sulfide-rich metallic ore

Dyed Alum or Dyed Quartz (Ornamental Crystal)

Silicon Dioxide (SiO2) or Potassium Alum [KAl(SO4)2·12H2O]

Sodalite

Sodalite (Na8(Al6Si6O24)Cl2)

Druzy Quartz (Botryoidal)

Silicon Dioxide (SiO2)

Likely tumbled jasper or agate

Microcrystalline quartz (SiO₂), possibly iron-rich jasper

Vesicular basalt (likely weathered scoria)

Basaltic scoria; predominantly calcium-rich plagioclase, clinopyroxene, and iron-magnesium oxides

Botryoidal chalcedony/geode fragment

Microcrystalline quartz (SiO₂), likely quartz-lined cavity with possible calcite

Hag Stone (Quartz Pebble with Natural Hole)

Quartz (Silicon Dioxide - SiO2)

Calcite with Quartz coating

Calcium Carbonate (CaCO3) with Silicon Dioxide (SiO2)

Dyed Agate

SiO2

Peridot (Olivine)

Magnesium Iron Silicate (Mg,Fe)2SiO4