Organic Material (Likely A Fruit Or Berry)

Chert (specifically Flint or Jasper variant)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Blue opalite (often sold as synthetic opal)

Opalite glass; amorphous hydrated silica if natural opal (SiO₂·nH₂O)

Mixed river pebbles and quartz-rich specimens

Polymictic fluvial gravel; likely quartz, quartzite, chert, and weathered feldspathic rocks

Chert (Smooth River Pebble)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Bornite (peacock ore), likely with chalcopyrite

Bornite, Cu5FeS4; associated copper sulfides may include chalcopyrite, CuFeS2

Weathered iron-stained quartzite or sandstone cobble

Quartzite (quartz-rich rock), possibly ferruginous sandstone

Chert (and Flint)

Silicon Dioxide (SiO2)

Chert (Yellow Jasper variant)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert with Iron Staining

Microcrystalline Quartz (SiO2)

Veined quartz-bearing metamorphic rock

Likely quartzite or siliceous schist with iron-oxide staining

Tumbled red jasper with a quartz vein

Jasper (microcrystalline quartz, SiO₂), likely crossed by milky quartz

Sandstone (likely Quartzose Sandstone)

Arenite (composed primarily of SiO2)

Sand Tiger Shark Tooth

Carcharias taurus

Likely weathered granite or granitic gneiss fragment

Granite; mainly quartz, feldspar, and mica

Pink-and-white quartz-rich rock, likely rose quartz or quartzite

Quartz (SiO₂), possibly rose-quartz-bearing quartzite; minor iron-oxide staining

Tumbled purple agate (likely grape agate or amethystine chalcedony)

Microcrystalline quartz, SiO₂; purple coloration commonly from iron, manganese, or inclusions

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly quartz (SiO₂), with minor feldspar, mica, and iron-oxide staining

Weathered brown mineralized rock

Likely iron-stained quartzite or quartz-rich metamorphic rock; exact identification requires testing

Chert (Nodule)

Chert (Cryptocrystalline Silica, SiO2)

Chert (Nodule/Common Chert)

Microcrystalline quartz (SiO2)

Chert (Jasper variety)

Microcrystalline quartz (SiO2)

Serpentinized ultramafic rock with magnesite

Serpentinite, chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with likely magnesite (MgCO₃) and minor chromite/magnetite

Goldstone (Red)

Aventurine Glass (Cupriferous glass)

Milky Quartz Geode Fragment

Silicon Dioxide (SiO2)

Amber Chert (Jasper)

Microcrystalline Quartz (SiO2)

Weathered porphyritic volcanic rock

Likely altered andesite or rhyolite porphyry

Weathered iron-rich sandstone or laterite fragment

Ferruginous sandstone, chiefly quartz (SiO₂) cemented or stained by iron oxides/hydroxides

Chert Cobble / Quartzite River Stone

Microcrystalline Quartz (SiO2) / Quartzite

Weathered quartz-rich rock, likely sandstone or quartzite

Quartz arenite (sandstone) or quartzite; predominantly SiO₂

Sandstone

Arenite (primarily SiO2)

Weathered granitic rock

Granite or granodiorite; mainly quartz, feldspar, and mica/amphibole

Travertine (Tufa)

Chemical Limestone (CaCO3)

Chalcedony (likely agate/chert variety)

Microcrystalline quartz, SiO₂

Polished green aventurine (likely)

Quartzite dominated by quartz (SiO₂), commonly containing fuchsite mica

Dark flint or chert fragment

Microcrystalline quartz (SiO₂), likely flint/chert

Chert (potentially Jasper)

Microcrystalline Quartz (SiO2)

Chert (variously identified as Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone (likely Arkose or Quartz Sandstone)

Clastic sedimentary rock (primarily SiO2)

Petrified Wood

Silicified Wood (SiO2)

Polished turquoise

Turquoise — hydrated copper–aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O

Sandstone (Quartzose)

Arenite (SiO2 based typically)

Jasper (Green/Yellow Moss Jasper)

Silicon Dioxide (SiO2)