Organic Gemstone (Not A Rock Or Mineral In The Traditional Sense, But Bio Mineralized Material)

Chert (Jasper/Flint variant)

Microcrystalline quartz (SiO2)

Polished fossiliferous limestone

Bioclastic carbonate rock, primarily calcite (CaCO₃)

Iron-stained rock fragment, possibly quartz-rich

Unidentified quartz-rich rock with iron-oxide staining (likely hematite/goethite)

Quartz

Silicon Dioxide (SiO2)

Likely coal (possibly anthracite)

Coal, composed chiefly of carbon-rich organic matter; rank cannot be confirmed from the photograph

Rounded river cobble, likely basaltic volcanic rock

Fine-grained mafic igneous rock; likely basalt or andesite

Rough amethyst-bearing quartz specimens

Quartz, SiO₂; purple coloration from trace iron and irradiation

Likely milky quartz, possibly quartz-rich vein rock

Quartz (SiO₂); identification from the image is uncertain

Shale

Mudrock / Fissile Shale

Petrified Wood

Silicified Wood (SiO2)

Diamond (in Matrix)

Carbon (C)

Weathered gray pebble

Likely fine-grained basalt or andesite; exact identification requires testing

Quartz (Iron-Stained)

Silicon Dioxide (SiO2)

Petrified Wood

Silicified wood (SiO2)

Fossiliferous Limestone (Coquina)

Calcite (CaCO3) with Bioclastic inclusions

Clear faceted gemstone in an ornate metal bracelet

Unidentified transparent faceted stone; possibilities include quartz (SiO₂), zircon (ZrSiO₄), or glass—image alone cannot distinguish them

Polished mixed rock, likely orbicular/epidote-bearing granite or basalt

Uncertain; probable quartz–feldspar–amphibole/epidote aggregate

Graphite-rich metamorphic rock (probable graphite schist)

Graphite schist; predominantly graphite (C) with quartz and mica

Turquoise (Rough)

CuAl6(PO4)4(OH)8·4H2O

Iron-stained fossiliferous rock, possibly fossil wood

Likely silicified/petrified wood in iron-rich silica matrix; exact identification requires microscopy

Copper Ore with Malachite and Chalcocite

Copper-bearing Mineral Assemblage (Cu2CO3(OH)2 + Cu2S)

Likely dark green-gray metamorphic pebble

Indeterminate; possibly chlorite schist, serpentinite, or amphibolite

Fossilized Bone

Permineralized Vertebrate Bone

Chert (Flint)

Silicon dioxide (SiO2)

Mammoth or Mastodon Tooth Fossil

Mammuthus / Mammut tooth

Shark Tooth Fossil

Vertebrate fossilized tooth (Chondrichthyes)

Fossil Shark Tooth

Selachimorpha (Chondrichthyes dental fossil)

Ruby

Corundum (Aluminium Oxide with Chromium impurities, Al2O3:Cr)

Blue Apatite

Apatite group (Ca5(PO4)3(F,Cl,OH))

Tumbled quartz-rich stone, possibly granite or rhyolite

Likely quartz (SiO₂) with feldspar and minor mica or other inclusions

Dendritic Agate (or Dendritic Opal)

SiO2 (for Agate), SiO2·nH2O (for Opal)

Polished agate or jasper cabochon

Cryptocrystalline quartz, SiO₂, possibly iron-rich jasper inclusions

Chalcedony on Matrix

Silicon Dioxide (SiO2)

Small stud earring with a purple gemstone (possibly amethyst)

Possible amethyst, a purple variety of quartz (SiO₂); identification is uncertain from the image

Petrified Wood

Silicified wood (SiO2)

Black Freshwater Pearls

Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3

Quartz-bearing geode or vuggy quartz specimen

Quartz, silicon dioxide (SiO₂), possibly with chalcedony and iron-oxide staining

Unidentified gray mineral/rock fragment

Indeterminate from image; possibly quartz-rich material or mica-bearing schist

Clear Quartz / Diamond (untested)

Silicon Dioxide (SiO2) or Carbon (C)

Yellow Jasper

Silicon Dioxide (SiO2) with hydrated iron oxide impurities (Goethite)

Boulder Opal

Hydrated Silica (SiO2·nH2O)

Shark Tooth Fossil

Carcharocles megalodon or similar fossilized shark tooth