Organic Material (Likely A Fruit Or Berry)

Flint or chert fragment

Microcrystalline quartz (SiO₂), likely flint/chert

Quartzite

Quartzite (SiO2)

Polished limestone or marble slab

Calcite-rich carbonate rock; likely marble (CaCO₃)

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide / Chalcedony)

Weathered iron-rich sandstone or laterite

Ferruginous sandstone; potentially lateritic ironstone, composed mainly of quartz (SiO₂) with iron oxides/hydroxides

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Milky Quartz (Water-worn Pebble)

Silicon Dioxide (SiO2)

Polished carnelian/chalcedony pebble

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony

Chert (Field Stone)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Sandstone (likely Quartz Sandstone)

Arenite (SiO2 based)

Sandstone (likely Quartzose Sandstone)

Arenite (SiO2 based)

Milky quartz-rich rock

Quartz (SiO₂), likely massive milky quartz with minor iron-oxide staining and attached host material

Black tourmaline beads (likely schorl)

Schorl, NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Weathered granite or granitic pegmatite cobble

Granite/granitic rock, composed mainly of quartz (SiO₂), feldspar, and minor biotite or other dark minerals; the reddish-brown areas may be iron-oxide staining or weathered accessory minerals

Tumbled honey calcite

Calcite (CaCO₃), likely iron-stained variety

Petrified Wood

Silicified Wood (SiO2)

Iron-stained quartzite or chert

Quartzite, predominantly SiO₂, with iron-oxide staining

Quartzite

Quartzite (primarily SiO2)

Worked chert (likely flint)

Microcrystalline quartz/chalcedony, SiO₂

Vesicular basalt (likely weathered lava rock)

Basalt, predominantly calcium-rich plagioclase, pyroxene, and commonly olivine; vesicular texture from gas bubbles

Chalcedony (likely iron-stained agate)

Microcrystalline quartz, SiO₂ (chalcedony/agate)

Tumbled blue chalcedony (likely blue quartz/chalcedony)

Cryptocrystalline silica, SiO₂; likely chalcedony, possibly dyed or surface-coated

Dark green metamorphic rock, likely serpentinite

Serpentinite, composed mainly of serpentine-group minerals (antigorite, lizardite, or chrysotile), commonly with magnetite and minor chlorite/talc

Dark rounded pebble, likely basalt or slag

Probable fine-grained mafic rock; possibly basalt (plagioclase–pyroxene) or industrial iron/steel slag

Chert / Jasper / Agate (Chalcedony Group)

Microcrystalline Quartz (SiO2)

Likely foliated metamorphic rock, possibly schist

Mica schist or micaceous quartzite; exact identification is uncertain from the photograph

Serpentinized ultramafic rock (likely serpentinite)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, olivine, pyroxene, and sulfides

Quartzite (likely iron-stained)

Quartzite; predominantly crystalline silicon dioxide (SiO₂)

Green Jasper

Silicon Dioxide (SiO2) with impurities

Ironstone Concretion / Limonite Node

Ferruginous Sedimentary Rock (composed primarily of Limonite FeO(OH)·nH2O and Goethite)

Likely quartz-rich rock fragment

Probably microcrystalline quartz (SiO₂), possibly a pale chert or quartzite fragment

Tumbled yellow jasper (likely serpentine or calcite-rich stone)

Jasper: microcrystalline quartz (SiO₂); exact yellow veining may indicate serpentine, calcite, or iron oxides

Tumbled banded metamorphic stone

Likely banded gneiss or migmatitic gneiss; exact identification requires testing

Granite pebble

Granite; chiefly quartz, potassium feldspar, plagioclase, and minor biotite/hornblende

Chert (and Jasper blend)

Chert (Microcrystalline Quartz, SiO2)

Unidentified weathered rock fragment

Likely granitic or feldspathic rock; exact identification requires clearer imaging and testing

Chert (often called Flint in this variation)

Silicon dioxide (SiO2) - Microcrystalline quartz

Porphyritic Basalt (or Andesite) Pebble

Porphyritic Mafic Volcanic Rock

Chert (Gravel specimen)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Common Variety)

Cryptocrystalline Quartz (SiO2)

Fossiliferous Limestone (Coquina / Shell Limestone)

Biogenic Limestone (Calcium Carbonate, CaCO3)