Man Made Byproduct (Non Geological)

Malachite

Malachite (Copper Carbonate Hydroxide) - Cu2CO3(OH)2

Polished leopard-skin jasper

Orbicular jasper; microcrystalline quartz/chalcedony (SiO₂) with iron-oxide inclusions

Red faceted gemstone ring

Likely synthetic ruby or red spinel; exact identification requires testing

Garden Pebble (Quartzite or Limestone fragment)

Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3) fragment

Chert (Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Pink calcite (likely)

Calcite — calcium carbonate, CaCO₃

Diamond (in jewelry setting)

Carbon (C)

Chert (Flint)

Silicon dioxide (SiO2)

Weathered granite

Granite, composed mainly of quartz, feldspar, and dark mica or amphibole

Pyrite in Matrix

Iron Sulfide (FeS2)

Polished dark gemstone, likely hematite or magnetite

Hematite (Fe₂O₃) or magnetite (Fe₃O₄); exact identification requires testing

Schist with Garnet inclusions

Garnet-mica-schist

Blue gemstone bead bracelet, likely dyed agate or another blue stone

Undetermined; possibly dyed chalcedony (microcrystalline quartz, SiO₂)

Quartzite Pebble

Metamorphic Quartzite (predominantly SiO2)

Small pale rock fragment

Indeterminate; possibly quartz, calcite, or a weathered feldspar-rich fragment

Obsidian

Obsidian (Volcanic Glass)

Black Obsidian

Volcanic Glass (SiO2)

Tumbled blue stone, likely sodalite

Sodalite, Na₈(Al₆Si₆O₂₄)Cl₂; identification uncertain from image alone

Chert Pebble

Chert (SiO2)

Granite

Granite (phaneritic intrusive igneous rock consisting of quartz, feldspar, and mica)

Diamond (in jewelry setting)

Adamantine Carbon (C)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Chert (Nodule)

Chert (Alpha-Quartz, SiO2)

Fossil bone or tooth fragment

Mineralized fossil vertebrate bone/tooth; exact taxon cannot be determined from the photograph

Chalcedony with iron-oxide staining

Microcrystalline quartz (SiO₂), likely chalcedony or chert with limonite/goethite staining

Chert (varieties include Flint and Jasper)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Sandstone (with potential Arkose/Lithic characteristics)

Arenite (Sedimentary rock composed of sand-sized grains)

Coquina / Fossiliferous Limestone

Coquina (composed primarily of Calcium Carbonate / CaCO3)

Coquina and Oyster Fossil Rock

Coquina limestone (Calcium Carbonate, CaCO3) containing fossilized Crassostrea / bivalve shells

Pyrite

Iron Sulfide (FeS2)

Iron-stained chert (flint) nodule

Microcrystalline quartz (SiO₂), with iron-oxide staining

Limonite (with goethite)

Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)

Grey River Stone (Quartz-rich Quartzite/Siltstone)

Quartzite / Meta-siltstone (primarily SiO2)

Cupronickel (on a 1981 Mexico 20 Pesos coin)

Copper-Nickel Alloy (Cu75Ni25)

Amber-like resin specimen

Likely amber (fossilized tree resin), commonly succinite; exact identification is uncertain from the image

Goldstone (Red)

Aventurine Glass

Smoky Quartz

Smoky Quartz (Silicon Dioxide, SiO2)

Obsidian

Volcanic Glass (70% or more SiO2)

Black Obsidian

Volcanic Glass (Silicon Dioxide with impurities)

Tumbled pale green aventurine or common green quartzite

Quartz, SiO₂, likely with fuchsite or chlorite inclusions

Chert (Flint)

Microcrystalline Quartz (SiO2)

Faceted colorless gemstone, likely cubic zirconia or quartz

Uncertain from photograph; cubic zirconia (ZrO₂) is the leading visual possibility, with quartz (SiO₂) as an alternative