Mineraloid (Human Made Geological Specimen)

Mixed rock and mineral collection

Multiple specimens; visible pieces may include quartz, calcite, agate/chalcedony, jasper, and dyed or coated materials

Note: Item is not a geological specimen

Guitar Components (Steel, Nickel, Plastic, Wood)

Green aventurine cabochon

Quartzite dominated by quartz (SiO₂), colored green by fuchsite mica or chlorite

Inscribed limestone fragment

Calcitic limestone (primarily CaCO₃), possibly marble if recrystallized

Mounted faceted gemstone ring

Likely diamond (carbon, C), though the image is insufficient for definitive identification

Blue faceted gemstone ring, likely synthetic sapphire or blue topaz

Uncertain from image; possible corundum (Al₂O₃) or topaz (Al₂SiO₄(F,OH)₂)

Concretion with Geode Cavity

Ferruginous Sandstone Concretion with Quartz Center

Carved quartz skull, likely smoky quartz or gray chalcedony

Silicon dioxide (SiO₂), quartz or microcrystalline quartz

Chert (Flint)

Silicon Dioxide (SiO2)

Man-made Carved Stone (Scream Mask/Skull motif)

Carved Soapstone or Serpentine-rich rock

Red-and-brown agate bead bracelet

Agate, a microcrystalline variety of quartz (SiO₂), likely colored chalcedony/carnelian

Chert / Flint (Arrowhead Artifact)

Microcrystalline quartz (SiO2)

Painted Sandstone

Sandstone (clastic sedimentary rock) with acrylic/artistic coating

Obsidian

Obsidian (volcanic glass)

Hand-Drawn Gengar Pokémon Card Artist Item

Lignocellulosic Fiber (Cellulose, C6H10O5) with wax-based pigment (crayon/colored pencil)

Tumbled green fluorite (probable)

Fluorite, calcium fluoride (CaF₂)

Possible weathered metal-rich rock or slag fragment

Uncertain; possibly iron-oxide-rich breccia or industrial slag

Tumbled cream-colored pebble, likely quartz or calcite

Indeterminate from photograph; possibilities include microcrystalline quartz (SiO₂) or calcite (CaCO₃)

Conglomerate

Clastic Sedimentary Rock (Conglomerate)

Chert

Microcrystalline quartz (SiO2)

Faceted blue gemstone ring, likely synthetic spinel or glass; identity uncertain

Possibly synthetic blue spinel (MgAl₂O₄) or laboratory sapphire (Al₂O₃); the clear side stones may be cubic zirconia or glass

Bismuth Crystal

Bismuth (Bi)

Tumbled greenstone / serpentinite (probable)

Serpentinite, chiefly Mg-rich serpentine minerals (antigorite, lizardite, chrysotile), possibly mixed with chlorite, magnetite, or carbonate

Asphalt Concrete (Bituminous Conglomerate)

Anthropogenic Bituminous Conglomerate

Chert / Flint

Microcrystalline Quartz (SiO2)

Chert (often called Flint)

Chert (Cryptocrystalline Quartz, SiO2)

Obsidian (likely black volcanic glass)

Obsidian; primarily amorphous volcanic silica glass, approximately SiO₂-rich rhyolitic composition

Lava Rock with Fabric Impression

Scoria or Basalt with anthropogenic impressions

Tumbled dark stone, likely basalt or slate

Basalt (fine-grained plagioclase–pyroxene rock), possibly slate/phyllite

Chert Nodule

Microcrystalline Quartz

Chert (often called Flint or Jasper if reddish)

Microcrystalline Quartz (SiO2)

Opalite

Synthetic Glass (Simulated Opal)

Dark blue polished stone pendant

Indeterminate; possibly sodalite, lapis lazuli, or blue slag/glass-like material

Tumbled pink-orange feldspar

Microcline or orthoclase feldspar, KAlSi₃O₈ (tentative)

Tumbled milky quartz

Quartz, silicon dioxide (SiO₂)

Tumbled blue glassy mineral specimen, possibly blue calcite or dyed quartz

Uncertain from image; likely calcite (CaCO₃) or dyed microcrystalline quartz (SiO₂)

Polished pink feldspar (likely moonstone/sunstone-type feldspar)

Alkali feldspar, commonly orthoclase or microcline; KAlSi₃O₈

Red coral (likely precious coral)

Corallium sp.; calcium-carbonate skeleton, primarily calcite

Cut quartz crystal (likely rock crystal)

Quartz, silicon dioxide (SiO₂), trigonal crystal system

Pearl oyster shell with cultured pearls

Mollusk shell (likely Pinctada spp.) containing aragonite pearls, CaCO₃

Snowflake Obsidian

Spherulitic Obsidian (Volcanic Glass with Cristobalite inclusions)

Banded agate tower (likely onyx/chalcedony)

Microcrystalline quartz, SiO₂; commonly called banded agate or black-and-white onyx