Mineraloid (Human Made Geological Specimen)

Quartz (Milky or Common Quartz)

Silicon Dioxide (SiO2)

Apatite

Apatite Group (e.g., Fluorapatite Ca5(PO4)3F, Chlorapatite Ca5(PO4)3Cl, Hydroxylapatite Ca5(PO4)3(OH))

Milky Quartz

Silicon Dioxide (SiO2)

Gastropod Fossil (Snail Internal Mold)

Gastropoda; internal mold (steinkern), often composed of Calcium Carbonate (CaCO3) or Silica (SiO2)

Sandstone with Ironstone Concretion

Arenite with Hematite/Goethite nodules (Fe2O3 / FeO(OH))

Biotite Schist

Biotite Schist (predominantly K(Mg,Fe)3AlSi3O10(OH,F)2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz (Crystal Point/Fragment)

Silicon Dioxide (SiO2)

Quartz with Mica inclusion

Silicon Dioxide (SiO2) with Muscovite/Biotite inclusions

Milky Quartz

Silicon Dioxide (SiO2)

Vanadinite

Vanadinite [Pb5(VO4)3Cl]

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

Granite

Granite (composed primarily of Quartz SiO2, Alkali Feldspar, and Plagioclase Feldspar)

Chert (Yellow Jasper)

Silicon Dioxide (SiO2)

Ironstone with Limonite/Goethite coating

Ferruginous Sedimentary Rock (contains Limonite FeO(OH)·nH2O)

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Unakite

Unakite (metasomatized granite)

Pyrite

Iron Sulfide (FeS2)

Chalcopyrite

Chalcopyrite (CuFeS2)

Quartz

Silicon Dioxide (SiO2)

Jasper (Green/Dragon Blood variety)

Silicon Dioxide (SiO2) with iron/clay inclusions

Granite

Granitoid (comprised of Quartz, Feldspar, and Mica)

Yellow Jasper

Silicon Dioxide (SiO2) with iron inclusions

Granite

Granite (High-silica plutonic rock)

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Granite

Phaneritic Felsic Igneous Rock (primarily SiO2, Al2O3, K2O, Na2O)

Optical Calcite (Iceland Spar)

Calcite (Calcium Carbonate, CaCO3)

Quartz (Variety of Rough Mineral Specimens)

Silicon Dioxide (SiO2)

Quartz Druze on Matrix

Silicon Dioxide (SiO2)

River Rock (Basalt/Greywacke)

Aphanitic Basalt or Lithic Sandstone (Greywacke)

Schist (Micaceous Schist)

Mica Schist

River Cobble (likely Basalt or Chert)

Siliceous River Rock / Microcrystalline Quartz / Mafic Igneous

Garden Quartz (Phantom Quartz)

Silicon Dioxide (SiO2) with inclusions (Chlorite, Feldspar, Goethite, Hematite)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Amethyst (Faceted)

Quartz (SiO2) with iron impurities

Slag (Industrial Glass/Metal)

Ferrous slag or Glassy silicate byproduct

Quartz Vein in Host Rock (Likely Slate or Shale)

Hydrothermal Quartz (SiO2) in Pelitic host rock

Limonite Sandstone

Ferruginous Sandstone (Hydrated Iron Oxide)

Flower Agate (Plume Agate)

Chalcedony (Silicon Dioxide) with Spherulitic Inclusions - SiO2

Pumice

Pumice (volcanic glass foam)

Schist

Mica Schist (Medium-grade metamorphic rock)

Limestone

Calcium Carbonate (CaCO3)