Mineral With Artificial Coating

Likely weathered quartz-bearing rock fragment

Indeterminate; appears to contain quartz (SiO₂) with iron-oxide staining, possibly from quartzite, granite, or pegmatite

Pink calcite

Calcite (CaCO₃), likely manganese-bearing

Weathered basalt (possibly vesicular basalt)

Basalt; chiefly plagioclase, pyroxene, and iron-titanium oxides

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrous ferric oxide)

Smoky quartz (likely faceted cabochon or rough fragment)

Quartz, silicon dioxide (SiO₂), smoky variety colored by irradiation-related defects

Tumbled orange chalcedony or quartzite

Microcrystalline quartz (SiO₂), possibly iron-stained chalcedony; exact identification requires testing

Drupa Quartz (Sparkly Drusy Quartz on Matrix)

Crystalline Silicon Dioxide (SiO2) on host rock

Heat-Treated Citrine (Amethyst)

Silicon Dioxide (SiO2) with iron impurities

Heat-Treated Amethyst (Commercial Citrine)

Silicon Dioxide (SiO2) with iron impurities

Heated Citrine (Heat-Treated Amethyst)

Silicon Dioxide (SiO2), quartz variety

Polished blue stone, likely sodalite or dyed agate

Sodalite: Na₈(Al₆Si₆O₂₄)Cl₂; exact identification requires testing

Sunkissed Quartz or Hematoid Quartz

Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions

Iron-stained quartz-rich rock, possibly weathered granite or quartzite

Indeterminate quartz–feldspar aggregate with iron-oxide staining; likely granitic or hydrothermal material

Quartz Pebble with Iron Oxide Staining

Silicon Dioxide (SiO2) with Hematite/Limonite coatings

Quartz Druzy (Quartz Druse)

Silicon Dioxide (SiO2)

Uvarovite

Ca3Cr2(SiO4)3

Ferruginous Quartz

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Aura Quartz (Rainbow Quartz)

Silicon Dioxide (SiO2) with metallic vapor coatings

Mystic Topaz

Aluminum silicate fluoride hydroxide with titanium coating (Al2SiO4(F,OH)2)

Dyed Purple Agate Sliced Tablet

Silicon Dioxide (SiO2), variety Chalcedony

Limonite with Ironstone

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

Red Sandstone

Clastic Terrigenous Sedimentary Rock (primarily SiO2 with Fe2O3 coating)

Red jasper (tumbled)

Jasper, microcrystalline quartz/chalcedony (SiO₂) colored mainly by iron oxides

Likely pink calcite or rose quartz

Calcite (CaCO₃) or quartz (SiO₂)

Possibly raw hematite or magnetite

Hematite (Fe₂O₃) or magnetite (Fe₃O₄)

Copper-stained quartz/igneous rock specimen

Quartz (SiO₂), with secondary copper minerals; host likely altered volcanic rock

Peacock ore

Iridescent chalcopyrite, commonly marketed as bornite

Smoky Quartz

Silicon Dioxide (SiO2)

Green Chalcedony (likely Green Agate or Chrysoprase)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Amethyst tumbled stones

Quartz, SiO₂; purple coloration from irradiation and trace iron

Quartz geode/druse, likely chalcedony matrix

Quartz, silicon dioxide (SiO₂), with possible microcrystalline chalcedony

Amethyst quartz crystal cluster

Quartz, SiO₂; purple coloration from irradiation and trace iron

Tumbled quartz-rich pebble

Likely quartz-bearing chert or jasper; primarily microcrystalline SiO₂

Tumbled quartz crystal (likely smoky or iron-stained quartz)

Quartz, silicon dioxide (SiO₂)

Quartz vein in iron-stained host rock

Quartz (SiO₂) with limonite/goethite staining, likely in altered basalt or another dark volcanic host

Honey calcite (orange calcite)

Calcite — calcium carbonate, CaCO₃

Quartz geode

Microcrystalline quartz and crystalline quartz (SiO₂), likely in a weathered volcanic or sedimentary host

Amethyst druzy geode

Quartz, SiO₂, purple variety (amethyst)

Polished smoky quartz pendant

Smoky quartz, silicon dioxide (SiO₂), colored by irradiation-related defects

Druzy Quartz

Crystalline Silicon Dioxide (SiO2)

Red Sandstone

Clastic Sandstone (typically Quartz-rich with Iron Oxide)

Pearl

Calcium Carbonate (Aragonite) with Conchiolin; formula: CaCO3