Mineral With Artificial Coating

Quartz vein in host rock

Quartz (SiO₂) in an undetermined mineralized host rock

Rose Quartz and Milky Quartz

Silicon Dioxide (SiO2)

Green iridescent glass cabochon or synthetic gemstone

Likely synthetic glass; possibly coated synthetic quartz or lab-created green gemstone

Quartz vein specimen

Quartz (SiO₂), likely drusy or massive quartz on host rock

Quartz geode with drusy quartz crystals

Quartz, silicon dioxide (SiO₂), commonly colorless to milky crystalline quartz

Quartz River Pebble (Iron-Stained)

Silicon Dioxide (SiO2) with Limonite/Hematite inclusions

Small fossilized tooth, possibly a shark tooth

Indeterminate fossil tooth; species cannot be identified from this image

Manganese Oxide Crust on Limestone

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

Tumbled carnelian/chalcedony

Carnelian, orange-red microcrystalline quartz (SiO₂), a variety of chalcedony

Red Sandstone

Sedimentary Litharenite / Quartz Arenite

Iron-rich mineral fragment, possibly limonite/goethite

Limonite (hydrated iron oxides; commonly goethite, FeO(OH), with hematite)

Limonite (Iron Ore)

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

Dyed Blue Agate

Silicon Dioxide (SiO2) with artificial cobalt-based dye

Iron Slag

Anthropogenic Vitreous Silicate (Byproduct of Smelting)

Peacock ore (likely chalcopyrite-bornite specimens)

Iridescent chalcopyrite, CuFeS₂, commonly altered to bornite, Cu₅FeS₄

Tumbled chalcedony (likely carnelian or common agate)

Microcrystalline quartz, SiO₂; chalcedony variety

Peridot (Olivine)

Magnesium Iron Silicate (Mg,Fe)2SiO4

Iron-stained quartzite or ironstone

Likely ferruginous quartzite, composed mainly of quartz (SiO₂) with iron oxides such as hematite and goethite

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily Quartz, SiO2)

Weathered metamorphic rock, likely schist or slate

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

Banded agate geode fragment

Microcrystalline quartz (chalcedony), SiO₂

Celadonite in Basalt (Green Earth)

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

Dyed blue-purple tumbled stone, likely quartz or calcite

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

Kaolinite (China Clay / Chalky Claystone)

Al2Si2O5(OH)4

Lemon Quartz

Silicon dioxide (SiO2) with iron inclusions

Dyed Howlite (Dyed Red)

Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)

Turquoise

Turquoise (CuAl6(PO4)4(OH)8·4H2O)

Sea Glass

Amorphous silicon dioxide (glass)

Desert Rose (Gypsum Rose)

Gypsum (CaSO4·2H2O)

Likely labradorite-bearing rock

Labradorite (plagioclase feldspar; approximately (Ca,Na)(Al,Si)₄O₈)

Iron-stained Quartz

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

Blue Goldstone

Man-made glass infused with copper crystals

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Druzy Quartz (Botryoidal)

Silicon Dioxide (SiO2)

Carved smoky quartz (likely)

Quartz, silicon dioxide (SiO₂), smoky variety

Dyed pink banded agate

Chalcedony (microcrystalline quartz), SiO₂, commonly dyed

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂), opaque-to-translucent milky variety

Fossilized Shark Tooth

Carcharocles sp. (likely Lemon or Sand Tiger)

Crackle Agate / Dyed Quartz

SiO2 (Silicon Dioxide)

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

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

Dyed Agate

SiO2 (Silicon Dioxide)

Sodalite

Sodalite (Na8(Al6Si6O24)Cl2)