Mineraloid (Human Made Geological Specimen)

Milky Quartz

Silicon Dioxide (SiO2)

Blue Glass or Slag Glass

Amorphous Silica (Anthropogenic Glass)

Chert Arrowhead (Lithic Artifact)

Chert (Cryptocrystalline Quartz, SiO2)

Jasper

Silicon dioxide (SiO2) with iron impurities

Sandstone (Quartzose Sandstone)

Clastic Terrigenous Sedimentary Rock (primarily SiO2)

Epidote Water-Worn Pebble

Epidote {Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)

Sunstone (Aventurine Feldspar)

(Ca,Na)((Al,Si)2Si2O8) with inclusions of Cu or Fe2O3

Sunstone

(Ca,Na)((Al,Si)2Si2O8) - Plagioclase Feldspar

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Chert / Jasper

Microcrystalline Quartz (SiO2)

Iron-stained quartz crystal

Quartz (SiO₂), likely iron-oxide-coated or included

Asphalt

Asphalt concrete (engineered material, not a naturally occurring rock/mineral in this form)

Rounded pebble, likely quartz-rich sandstone or chert

Indeterminate lithic clast; possibly quartz arenite or microcrystalline quartz (SiO₂)

Pyrite

Iron Disulfide (FeS2)

Iron-stained Quartz

Silicon Dioxide with Iron Oxide (SiO2 + Fe2O3)

Quartzite with Iron Mineral Banding

Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3) staining

White chalcedony or quartz-rich pebble

Microcrystalline quartz (SiO₂), possibly with minor calcite or feldspar

Vein-bearing sandstone or quartzite cobble

Quartz-rich sandstone with white quartz veins; possibly metamorphosed to quartzite

Green Agate

Cryptocrystalline Quartz (SiO2)

Jasper

Jasper (Silica-rich Microcrystalline Quartz, SiO2)

Sandstone (Micaceous/Feldspathic variant)

Arenite (specifically subarkose or lithic arenite)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Satin Spar (Gypsum)

Hydrous Calcium Sulfate (CaSO4·2H2O)

Pink Granite

Granite (Felsic Plutonic Rock)

Sandstone (specifically Arkose or Ferruginous Sandstone)

Sandstone (SiO2 predominant)

Granite

Phaneritic Felsic Igneous Rock (Granite)

Granite

Phaneritic Felsic Intrusive Igneous Rock

Basalt

Basalt (Mafic volcanic rock)

Chalk

Calcium carbonate (CaCO3)

Milky Quartz Pebble

Crystalline Silicon Dioxide (SiO2)

Tumbled or cut iron-rich mineral specimen

Likely limonite/goethite (hydrated iron oxides), possibly weathered hematite

Rhodochrosite

Manganese Carbonate (MnCO3)

Citrine

Silicon Dioxide (SiO2) with iron impurities

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Quartz on Matrix

Silicon Dioxide (SiO2)

Quartzite with Chlorite/Epidote

Metamorphosed Quartzite (SiO2)

Calcite (likely chalky calcite fragment)

Calcite, calcium carbonate (CaCO₃)

Quartz (Sand Grain size)

Silicon Dioxide (SiO2)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Garnet in Schist or Pegmatite

Almandine Garnet (Fe3Al2(SiO4)3) in host rock

Sandstone Concretion

Clastic Sedimentary Concretion (primarily SiO2 with Fe2O3 cement)

Quartz with Chlorite / Greenschist

Quartz vein in Greenschist (SiO2 with Chlorite group minerals)