Anthropogenic Material

Diamond

C (Carbon)

Tumbled pegmatitic rock, likely amazonite-bearing granite

Granite/pegmatite composed mainly of quartz, feldspar, and mica; blue-green area may be microcline (amazonite)

Vesicular volcanic rock, likely weathered pumice or scoria

Pumice/scoria; predominantly volcanic glass and feldspar, with possible iron oxides

Jasper

Silicon Dioxide (SiO2)

Milky quartz pendant

Quartz (silicon dioxide, SiO₂)

Diamond (or Simulant)

Carbon (C) or relevant simulant formula (e.g., ZrO2 for Cubic Zirconia)

Likely chert/flint fragment

Microcrystalline quartz (SiO₂), possibly partially weathered chert

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)

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

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

Laterite (Iron-rich bauxite or Gossan)

Ferricrete (Fe2O3·nH2O)

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)

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

Polished dendritic agate or jasper pebble

Microcrystalline quartz (SiO₂), likely chalcedony with iron-oxide inclusions

Polished amethyst-bearing quartz

Quartz, SiO₂; purple coloration from irradiation and trace iron

Polished tiger’s-eye cabochon (probable)

Quartz variety, SiO₂, with fibrous riebeckite/crocidolite-derived inclusions

Polished brecciated turquoise-like copper mineral

Likely chrysocolla–malachite–limonite assemblage; possibly turquoise-bearing copper ore

Petrified Wood

Silicified Wood (SiO2 as Quartz/Chert/Chalcedony)

River Rock

N/A - Generic term for water-smoothed rock

Quartzite with inclusions

Quartzite

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

Yellow-brown jasper or silicified volcanic rock

Microcrystalline quartz (chalcedony), SiO₂, likely jasper

Gold-bearing quartz or ironstone fragment

Quartz (SiO₂) with possible native gold and iron oxides

Asphalt (Aggregate)

Bituminous macadam / Concrete Aggregate

Carnelian/chalcedony rough

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

Sandstone

Arenite (primarily Quartz, SiO2)

Red corundum (ruby rough)

Corundum, aluminum oxide (Al₂O₃); ruby is chromium-bearing red corundum

Likely serpentinized ultramafic rock (serpentinite)

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

Likely quartz-rich metamorphic rock (quartzite)

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with mica or feldspar

Tumbled greenstone (likely serpentine or nephrite jade)

Serpentine-group minerals, commonly antigorite; possibly nephrite, a fibrous aggregate of amphibole (actinolite–tremolite)

Rounded river pebble, likely quartz-rich sandstone or weathered quartzite

Indeterminate; probable quartz (SiO₂)-rich clastic rock