Man Made Object (Metalwork)

Obsidian

Volcanic Glass (predominantly SiO2)

Quartz

Silicon Dioxide (SiO2)

Shale with Pyrite

Clastic sedimentary rock containing Iron Disulfide (FeS2)

Milky Quartz

Silicon Dioxide (SiO2)

Sandstone

Arenite (SiO2 based)

Quartzite Pebble

Metamorphic Quartz (SiO2)

Magnetite (likely with weathered Limonite/Hematite)

Magnetite (Fe3O4) with iron oxide weathering

Sandstone

Arenite (primarily SiO2)

River Pebble (Gneiss or Quartzite variant)

Course-grained Metamorphic Rock (likely SiO2 dominant)

Sandstone

Arenite (primarily SiO2)

Yellow Ochre / Limonite

Limonite (inter-mixed iron oxides and hydroxides, primarily FeO(OH)·nH2O)

Fossiliferous Limestone (Coral Fossil)

Scleractinian Coral in Calcium Carbonate (CaCO3)

Quartz (Quarzite or Massive Quartz vein)

Silicon Dioxide (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Clear Quartz

Silicon Dioxide (SiO2)

Sandstone (Quartzose Sandstone)

Clastic Sedimentary Rock (primarily SiO2)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Sandstone

Arenite (primarily SiO2)

Amber / Copal

Organic resin, C10H16O

Sandstone (with potential iron-oxide staining)

Arenite (primarily SiO2)

Bauxite

Bauxite (Mixture including Gibbsite Al(OH)3, Boehmite γ-AlO(OH), and Diaspore α-AlO(OH))

Milky Quartz

Silicon dioxide (SiO2)

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily Quartz with Fe2O3 staining)

Sandstone (Quartz-rich)

Arenite (SiO2 based)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Milky Quartz with Iron Inclusions

Silicon Dioxide (SiO2)

Quartzite (River Pebble)

Metamorphosed Quartz Sandstone (primarily SiO2)

River Cobble (likely Quartzite)

Metamorphosed Sandstone (SiO2)

Chert (Flint nodule)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Shale (sub-type: Carbonaceous Shale)

Lutaceous Sedimentary Rock

Blue Calcite

Calcium Carbonate (CaCO3)

Marble (White)

Metamorphosed Limestone (mainly CaCO3)

Satin Spar (Gypsum)

Hydrous Calcium Sulfate (CaSO4·2H2O)

Iron Ore (Limonite and Hematite)

Goethite/Limonite (FeO(OH)·nH2O) and Hematite (Fe2O3)

Sandstone (likely Quartzose Sandstone)

Arenite (composed primarily of SiO2)

Clear Quartz

Silicon dioxide (SiO2)

Fossiliferous Limestone

Fossiliferous Calclutite / Bio-calcarenite (CaCO3)

Clear Quartz crystals on a Matrix base (Geode fragment)

Silicon Dioxide (SiO2)

Quartzite

Quartzite (SiO2)

Gold (10K Alloy)

Aurum (Au) with alloying metals (Cu, Ag, Zn)

Quartz

Silicon Dioxide (SiO2)

Sandstone (likely Arkose or Quartz Sandstone)

Clastic sedimentary rock (primarily SiO2)