Man Made Object (Metalwork)

Polished rose quartz

Rose quartz (quartz), SiO₂

Fluorite

Calcium Fluoride (CaF2)

Banded Agate

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Red jasper (likely iron-rich chert)

Microcrystalline quartz (SiO₂), colored by hematite/goethite; possibly brecciated jasper

Polished brown jasper (likely ocean or brecciated jasper)

Microcrystalline quartz/chalcedony, SiO₂, colored mainly by iron oxides

Red synthetic corundum (ruby-colored lab-grown sapphire)

Corundum, aluminum oxide (Al₂O₃), likely synthetic and chromium-colored

Fossilized ammonite (likely weathered ammonite cross-section)

Ammonoidea; commonly Jurassic–Cretaceous ammonite fossils replaced by calcite or aragonite

Tumbled gray stone, likely serpentinite or weathered basalt

Tentatively serpentinite (predominantly serpentine-group minerals); identification is uncertain from the photograph

Polished kambaba jasper

Orbicular stromatolitic jasper; microcrystalline quartz (SiO₂) with chlorite/amphibole-rich inclusions

Tumbled rhodonite

Rhodonite, manganese inosilicate (MnSiO₃), commonly mixed with quartz and manganese oxides

Obsidian

Volcanic Glass (Amorphous SiO2)

Common Opal (Potch)

Hydrated Silica (SiO2·nH2O)

Snowflake Obsidian (or similar porphyritic volcanic rock)

Obsidian with Spherulites (if glassy), or Porphyritic Rhyolite/Andesite (if crystalline groundmass)

Yellow Jasper

Silicon Dioxide (SiO2) with iron inclusions

Red Jasper

Argillaceous microcrystalline quartz (SiO2 with Fe2O3 inclusions)

Snowflake Obsidian (Tumbled)

Obsidian with Cristobalite inclusions

Anthracite Coal

Anthracite (Carbon-rich metamorphic coal)

Fluorite

Calcium Fluoride (CaF2)

Jasper (Banded Jasper)

Silicon Dioxide (SiO2) with impurities

Smoky Quartz (with possible Feldspar inclusions)

Silicon Dioxide (SiO2)

Green Aventurine

Aventurine (a variety of Quartz, SiO2)

Orange Calcite (Polished Sphere)

Calcium Carbonate (CaCO3)

Blue Chalcedony

Chalcedony (Silicon Dioxide, SiO2)

Crushed Limestone

Calcium Carbonate (CaCO3)

Chert (Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Likely black beach pebble

Undetermined; possibly basalt, chert, or dark slate

Marble

Marble (metamorphosed limestone/dolostone). Predominantly composed of Calcite (CaCO3) for marble derived from limestone, or Dolomite (CaMg(CO3)2) for marble derived from dolostone.

Green Aventurine

Aventurine (Silicon dioxide, SiO₂)

Tumbled serpentine

Serpentinite; chiefly serpentine-group minerals, Mg3Si2O5(OH)4

Selenite (gypsum)

Gypsum, CaSO₄·2H₂O; variety: selenite

White Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Fossilized Stingray Mouth Plate

Myliobatidae gen. et sp. indet. (e.g., Myliobatis, Aetobatus)

Petoskey Stone

Hexagonaria percarinata

Pyrite

Iron Disulfide (FeS2)

Asphalt (Bituminous Concrete)

Bituminous mix / Anthropogenic conglomerate

Metal Alloy (Jewelry)

Not a naturally occurring rock or mineral; likely a metal alloy for jewelry. Possible compositions include sterling silver (92.5% silver, 7.5% copper), or other silver/gold alloys.

Green Glass Cullet / Recycled Glass

Amorphous Silicon Dioxide (SiO2) with various metal oxides

Red jasper

Microcrystalline quartz (SiO₂), iron-oxide-rich chalcedony

Raw green fluorite (probable)

Fluorite, calcium fluoride (CaF₂)

Polished blue banded agate cabochon/ornamental slab

Microcrystalline quartz (chalcedony), SiO₂, with blue coloring or inclusions

Polished/tumbled jasper

Jasper, microcrystalline quartz (SiO₂) with iron-oxide and other mineral impurities

Polished chert or jasper cobble

Microcrystalline quartz (SiO₂), commonly called chert; iron-oxide-bearing varieties are jasper