Anthropogenic (Man Made Material Processed By Nature)

Quartzite

Quartzite (SiO2-rich metamorphic rock)

Travertine (often colloquially called Tufa)

Chemical Sedimentary Calcium Carbonate (CaCO3)

Jasper

Chalcedony (cryptocrystalline quartz), SiO2

Granite

Granite (a common igneous rock)

Laterite

Laterite (Iron- and aluminum-rich rock)

Red Quartzite (Stream-rounded Cobble)

Meta-quartzite (SiO2 with Hematite impurities)

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)

Petrified Wood

Silicified Wood (SiO2 permineralization)

Petrified Wood

Silicified wood (primarily SiO2)

Serpentinite (Serpentine Rock)

Primarily composed of serpentine group minerals, such as antigorite, chrysotile, and lizardite. Chemical formula for serpentine minerals is (Mg,Fe)3Si2O5(OH)4.

Ferruginous Sandstone (Ironstone)

Arenite with Limonite/Goethite cement

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Sandstone

Arenite (SiO2 with various cementation agents)

Grey Slate

Foliated Metamorphic Rock (formed by low-grade regional metamorphism of shale or mudstone)

Quartz in Matrix (possibly Basalt or Siltstone host)

Silicon Dioxide (SiO2) in Host Rock

Diamond

Carbon (C), specifically a solid form of the element carbon with atoms arranged in a crystal structure called diamond cubic.

Chert (Commonly known as Flint)

Microcrystalline Quartz (SiO2)

Green aventurine quartz (probable)

Quartz, SiO₂, with fuchsite or other green mica inclusions

Serpentinite

Serpentinite (Mg, Fe, Ni)₃Si₂O―(OH)₄

Pink Granite

Felsic Plutonic Rock (primarily Quartz, Potassium Feldspar, and Plagioclase)

Petrified Wood (Silicified Wood)

Silicified Wood (primarily Chalcedony/Quartz, SiO2)

Sand Tiger Shark Tooth

Carcharias taurus

Ferruginous Quartz (Iron-stained Quartz)

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Sandstone (Quartzose Sandstone)

Clastic Sedimentary Rock (primarily SiO2)

Pink Granite

Phaneritic intrusive igneous rock with dominant Alkali Feldspar

Green Aventurine (Green Quartzite)

Silicon Dioxide (SiO2) with inclusions of Fuchsite (chromium-rich mica)

Limestone

Calcium Carbonate (CaCO3)

Rose quartz cabochon (probable)

Quartz, silicon dioxide (SiO₂); pink color typically caused by trace elements and microscopic inclusions

Diamond

Diamond (C)

Pebble (likely Quartzite or Chert)

Clastic Sediment, potentially composed of SiO₂ (Quartz)

Diamond

Diamond (C)

Tektite (likely Australite)

Tektite (no specific chemical formula as it's a natural glass of variable composition, mostly SiO2, Al2O3, FeO, MgO, CaO, K2O, Na2O, TiO2)

Polymictic breccia, possibly volcanic breccia

Polymictic clastic breccia; likely a matrix-supported breccia containing lithic fragments, quartz, feldspar, and dark mafic minerals

Conglomerate

Conglomerate (a clastic sedimentary rock)

Calcite

Calcite (CaCO3)

Oak-grain Laminate (Industrial/Decorative Furniture Finish)

Melamine Resin-impregnated Decorative Paper on Particleboard (Cellulose/Thermosetting Plastic)

Laterite (iron-rich nodule, possibly Bauxite as a subtype)

Laterite (composed of various minerals including goethite, hematite, gibbsite, etc.)

Jasper Breccia

Brecciated Jasper (Silicon Dioxide with Iron Oxide inclusions, SiO2)

Basalt (River Stone)

Aphanitic Mafic Igneous Rock

Greenschist

Greenschist facies rock

Quartz

Quartz (SiO2, Silicon Dioxide)

Quartz (likely macrocrystalline variety)

Quartz (SiO₂)