Anthropogenic Material

Milky quartz pendant

Quartz (silicon dioxide, SiO₂)

Laterite (Iron-rich bauxite or Gossan)

Ferricrete (Fe2O3·nH2O)

River Rock

N/A - Generic term for water-smoothed rock

Quartzite with inclusions

Quartzite

Tumbled magnesite

Magnesite (MgCO₃), likely compact or veined magnesite

Labradorite-bearing rough stone (tentative)

Labradorite, a calcium-rich plagioclase feldspar; possible mafic host rock

Scoria (vesicular volcanic rock)

Basaltic scoria; chiefly plagioclase, pyroxene, olivine, and iron-rich volcanic glass

Limestone

Calcium Carbonate (CaCO3)

Tumbled pale-green stone, likely prehnite or serpentine

Most consistent with massive prehnite, Ca₂Al₂Si₃O₁₀(OH)₂; serpentine is a possible alternative

Likely basalt pebble

Basalt; fine-grained mafic volcanic rock, chiefly plagioclase and pyroxene with possible olivine

Pink Quartzite

Quartzite (principally Silicon Dioxide, SiO2)

Coquina

Biogenic Limestone (mostly Calcium Carbonate, CaCO3)

Iron-rich laterite (hematitic limonite)

Laterite composed mainly of hematite (Fe₂O₃), goethite (FeO(OH)), and hydrated iron oxides

Sea Glass (specifically Frosted White)

Amorphous Silica (substance: Sodium-calcium silicate glass)

Iron Slag

Vitreous glassy waste (Fe-Si-Al-Ca compounds)

Green glassy gemstone-like specimen

Likely synthetic glass or treated quartz; exact identification requires testing

Orbicular jasper (often sold as leopard-skin jasper)

Silicified volcanic tuff/rhyolite; chiefly microcrystalline quartz and chalcedony (SiO₂), with iron oxides and altered volcanic minerals

Polished brecciated jasper or iron-rich agate

Microcrystalline quartz (SiO₂), with hematite/goethite and possible iron oxides

Tumbled quartz-rich pebble

Microcrystalline quartz (SiO₂), possibly chalcedony or quartzite

Tumbled dark limestone or basalt with a pale mineral vein

Likely micritic limestone (calcite, CaCO₃), possibly basalt with a calcite/quartz vein

Petrified Wood

Silicified Wood (SiO2)

Polished ocean jasper (orbicular jasper)

Silicified volcanic rock; chiefly microcrystalline quartz/chalcedony (SiO₂), with iron oxides and other alteration minerals

Light-colored quartz-rich pebble

Likely quartz (silicon dioxide, SiO₂), possibly a weathered quartzite fragment

Polished pietersite cabochon

Pietersite (brecciated fibrous quartz/chalcedony, commonly with riebeckite or crocidolite remnants)

Polished ocean jasper / orbicular jasper

Silicified rhyolite or chalcedony-rich microcrystalline quartz (SiO₂), commonly sold as ocean jasper

Petrified Wood

Silicified Wood (SiO2)

Brecciated jasper/chert

Microcrystalline quartz (SiO₂), with iron-oxide and clay inclusions

Ironstone concretion

Iron-oxide-cemented sediment, commonly goethite (FeO(OH)) and hematite (Fe₂O₃)

Likely chert/flint fragment

Microcrystalline quartz (SiO₂), possibly partially weathered chert

Carnelian/chalcedony rough

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

Weathered quartz-bearing rock, possibly serpentine or altered ultramafic rock

Provisional identification: serpentinite or chlorite–quartz schist; exact composition requires testing

Milky quartz

Quartz (silicon dioxide, SiO₂)

Sandstone

Arenite (primarily Quartz, SiO2)

Polished brown pebble, likely jasper or iron-stained quartzite

Uncertain; possible microcrystalline quartz (SiO₂) with iron-oxide staining

Tumbled Black Stone

Unknown (possibly basalt, obsidian, or black jasper)

Likely green aventurine or serpentine-bearing stone

Indeterminate from image; possibly quartzite with fuchsite mica or serpentinized ultramafic rock

Tiger’s-eye fragment

Chatoyant quartz, SiO₂, with pseudomorphic iron-oxide fibers

Quartz-rich pegmatitic rock (likely milky quartz with feldspar and dark mica)

Pegmatite; predominantly quartz (SiO₂), with feldspar and biotite/hornblende

Basaltic Tuff / Volcanic Breccia

Pyroclastic Breccia / Lithic Tuff

Brecciated Jasper

SiO2

White jade (likely nephrite) beads

Nephrite jade, an interlocking amphibole aggregate dominated by tremolite–actinolite; exact identification requires testing

Pink amethyst (likely), rough crystal fragment

Quartz, SiO₂; pink coloration may reflect iron-related inclusions or irradiation