Mineral Specimen

Hematite

Hematite (Fe2O3)

Amethyst

Amethyst (Silicon Dioxide - SiO2 with iron impurities)

Aquamarine

Beryl (Be3Al2Si6O18)

Calcite

Calcium Carbonate (CaCO3)

Black Tourmaline (Schorl)

NaFe2+3Al6(BO3)3Si6O18(OH)4

Chrysocolla (with Quartz and Malachite)

Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O

Pyrite

Iron Sulfide (FeS2)

Smoky Quartz

Silicon Dioxide (SiO2)

Honey Calcite

Calcite (Calcium Carbonate, CaCO3)

Specular Hematite (Specularite)

Iron Oxide (Fe2O3)

Blue Calcite

Calcite (CaCO3)

Sunstone

Heliolite (Oligoclase or Orthoclase Feldspar), (Ca,Na)(Al,Si)4O8

Ironstone / limonite-rich concretion

Hydrated iron oxides, chiefly limonite/goethite (FeO(OH)·nH₂O), possibly with hematite

Likely quartz-bearing mineral aggregate

Quartz (SiO₂), possibly mixed with mica or feldspar

Calcite (or Travertine / Limestone)

Calcium Carbonate (CaCO3)

Smoky quartz-bearing pegmatitic rock

Quartz, SiO₂, likely with feldspar and mica inclusions

Raw Ruby (Corundum)

Corundum (Aluminum Oxide, Al2O3)

Iron-rich botryoidal limonite/goethite specimen

Limonite (amorphous hydrated iron oxides, chiefly goethite, α-FeO(OH))

Smoky Quartz

Silicon Dioxide (SiO₂)

Agate

Silicon Dioxide (SiO2)

Calcite on Limestone (or Fossil)

Calcium Carbonate (CaCO3)

Chert Nodule / Flint

Microcrystalline Quartz (SiO2)

Fuchsite (Green Muscovite in Quartz)

K(Al,Cr)2(AlSi3O10)(OH)2 - Chromium-rich Muscovite

Amethyst

Silicon Dioxide (SiO2)

Gneiss with Iron Staining and Sulfide Mineralization

Metamorphic Gneiss / Amphibolite with Iron/Sulfide Oxidation

Ferruginous Quartz (Iron-stained Quartz)

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Pegmatite with Schorl (Black Tourmaline) and Mica

Pegmatite (complex association of NaAlSi3O8, NaFe3Al6(BO3)3Si6O18(OH)4, and KAl2(AlSi3O10)(OH,F)2)

Green Fluorite

Calcium Fluoride (CaF2)

Calcite crystal cluster (dogtooth/saddle calcite)

Calcite — calcium carbonate, CaCO₃

Milky quartz

Quartz (silicon dioxide, SiO₂)

Orange Calcite

Calcium Carbonate (CaCO3)

Lepidolite

K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2

Prehnite

Prehnite, Ca2Al(AlSi3O10)(OH)2

Epidote

Epidote (Ca2(Al,Fe)3(SiO4)3(OH))

Amazonite

Potassium feldspar (Microcline) - K(AlSi3O8)

White Calcite (Dogtooth Spar or Crystalline Calcite)

Calcite (Calcium Carbonate, CaCO3)

Emerald in Schist (Raw/Tumbled)

Beryllium Aluminum Silicate (Be3Al2Si6O18) with Chromium/Vanadium impurities in Mica Schist

Quartz / Quartzite

Quartz (Silicon Dioxide, SiO2)

Aquamarine

Beryl (Be3Al2Si6O18 with trace Fe2+)

Quartz with Mica/Chlorite inclusions

Silicon Dioxide (SiO2) with phyllosilicate inclusions

Green Fluorite

Fluorite (Calcium Fluoride - CaF2)

Aquamarine with Quartz

Beryl (Be3Al2Si6O18) with Quartz (SiO2)