Mineral With Artificial Coating

Peacock Ore (Bornite or Iridescent Chalcopyrite)

Bornite (Cu5FeS4) or Acid-treated Chalcopyrite (CuFeS2)

Ferruginous Sandstone

Sandstone (rich in iron oxides/hydroxides)

Calcite

Calcite (CaCO₃), likely honey/yellow calcite

Weathered granite or granitic pegmatite fragment

Granite, primarily quartz, alkali feldspar, and plagioclase; exact identification is limited by the photograph

Red Sandstone

Sedimentary Clastic Rock (Quartz Arenite)

Limonite (Iron Ore)

Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)

Granite-like rock fragment

Likely leucocratic granite or granitic pegmatite; exact identification requires a fresh surface and mineral testing.

Druzy Quartz on Matrix

Silicon Dioxide (SiO2) on host rock

Ferruginous Quartz

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

Tumbled quartz pebble

Quartz, silicon dioxide (SiO₂), likely milky quartz

Possible tumbled jasper or iron-rich chert

Microcrystalline quartz (SiO₂), commonly colored by iron oxides

Sandstone with Desert Varnish

Arenite (SiO2 predominantly) with Ferromanganese coating

Reddish-brown river pebble

Likely ferruginous sandstone or weathered reddish volcanic rock; exact identification requires a fresh surface and tests

Red Sandstone

Arenite (Ferruginous Sandstone)

Sandstone (with Iron Oxide)

Arenite with Limonite/Hematite staining

Aura Quartz (Anomalously Coated Quartz)

Silicon Dioxide (SiO2) treated with vaporized metals

Hematite bead bracelet

Hematite (iron(III) oxide, Fe₂O₃), likely polished magnetic hematite or hematite-coated beads

Ferruginous Quartz (Iron-stained Quartz)

Quartz with Iron Oxide inclusions (SiO2 with Fe2O3)

Botryoidal hematite–goethite specimen (probable)

Hematite (Fe₂O₃) with goethite (FeO(OH)), possibly limonite

Smoky quartz

Quartz, silicon dioxide (SiO₂), brown to gray variety

Lapis Lazuli

Lapis Lazuli (Complex rock mainly composed of Lazurite, Calcite, and Pyrite)

Smoky Quartz

Silicon Dioxide (SiO2) with aluminum impurities

Blue Chalcedony (Agate)

Silicon Dioxide (SiO2)

Druzy Quartz (part of a Geode)

Silicon Dioxide (SiO2)

Quartz with Iron Inclusions

Silicon Dioxide (SiO2) with Hematite or Limonite staining

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Tumbled hematite-rich ironstone

Hematite (Fe₂O₃), likely mixed with magnetite and iron-bearing silicates

Citrine quartz crystal

Quartz, silicon dioxide (SiO₂); yellow variety commonly called citrine

Blue Dyed Agate Geode (Slice)

Silicon Dioxide (SiO2) - Chalcedony / Quartz

Dyed Agate Geode Slice

Silicon Dioxide (SiO2)

Likely weathered quartz-rich rock fragment

Indeterminate; possibly quartz-bearing sandstone or chert with iron-oxide staining

Milky quartz with iron-oxide staining

Quartz, silicon dioxide (SiO₂), likely massive quartz; secondary iron oxides/hydroxides

Polished agate with druzy quartz

Microcrystalline chalcedony (SiO₂) with crystalline quartz and iron-oxide inclusions

Mystic Topaz

Aluminum Silicate Fluoride Hydroxide (Al2SiO4(F,OH)2) with metallic film coating

Druzy Quartz

Silicon Dioxide (SiO2)

Tumbled basalt pebble

Basalt, a fine-grained mafic volcanic rock; commonly plagioclase, pyroxene, and minor olivine or magnetite

Yellow tumbled stone, likely citrine or yellow calcite

Quartz (SiO₂), if citrine; alternatively calcite (CaCO₃)

Aura Quartz (Cranberry or Magenta Aura Quartz)

Silicon dioxide coated with titanium/niobium (SiO2)

Aura Quartz

Titanium/Titanium-Gold treated Silicon Dioxide (SiO2)

Quartz (Iron-Stained)

Silicon Dioxide (SiO2)

Ironstone Concretion (Desert Varnish / Hematite-Goethite Nodule)

Iron oxide / hydroxide deposit (predominantly Fe2O3 and FeO(OH))

Copper-bearing sulfide ore, possibly chalcopyrite-rich

Chalcopyrite (CuFeS₂), possibly with bornite and oxidation products