Biogenic Material

Vesicular volcanic rock, likely weathered scoria

Scoria (vesicular basaltic-andesitic volcanic rock), composition approximately plagioclase, pyroxene, and volcanic glass

Tumbled milky quartz

Quartz, silicon dioxide (SiO₂)

Amethyst cluster

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation

Sandstone

Arenite (composed primarily of SiO2)

Limestone

Calcium Carbonate (CaCO3)

Chert (or Flint)

Microcrystalline Quartz (SiO2)

Quartzite

Quartzite (primarily SiO2)

Limestone

Limestone (Calcium Carbonate, CaCO3)

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

Diamond (or Simulant)

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

Milky quartz pendant

Quartz (silicon dioxide, SiO₂)

Iron-rich laterite (hematitic limonite)

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

Likely chert/flint fragment

Microcrystalline quartz (SiO₂), possibly partially weathered chert

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

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

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)

Likely green aventurine or serpentine-bearing stone

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

Laterite (Iron-rich bauxite or Gossan)

Ferricrete (Fe2O3·nH2O)

Tumbled Black Stone

Unknown (possibly basalt, obsidian, or black jasper)

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

Polished brown pebble, likely jasper or iron-stained quartzite

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

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)

Polished brecciated turquoise-like copper mineral

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

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