Organic Gem Material (Botanical)

Pyrite (Fool's Gold) Cube

Iron Sulfide (FeS2)

Fossiliferous Limestone

Calcium Carbonate (CaCO3)

Diamond (Cut Specimen)

Diamond (pure carbon, C)

Olivine-rich peridotite / olivine crystal fragment

Olivine, typically (Mg,Fe)₂SiO₄; possibly peridotite if the specimen is rock rather than a single crystal

Petrified Wood (Silicified Fossil)

Silicified Wood (SiO2)

Ammonite fossil

Fossilized ammonoid cephalopod; likely an ammonite such as *Ammolytoceras* or a related Jurassic–Cretaceous genus

Chert (Jasper/Limonitic Chert)

Silicon dioxide (SiO2)

Quartz-rich chalcedony (likely jasper or agate)

Microcrystalline quartz, SiO₂; fibrous chalcedony with iron-oxide inclusions

Blue kyanite

Kyanite (Al₂SiO₅)

Malachite cabochon or polished bead

Malachite, Cu₂CO₃(OH)₂

Polished ruby-in-zoisite (anyolite), probable

Ruby-bearing zoisite; zoisite Ca₂Al₃(SiO₄)₃(OH), with corundum Al₂O₃

Blue-gray chalcedony (likely common quartz/chert)

Microcrystalline quartz, SiO₂; possibly weathered chert or chalcedony

Tumbled labradorite (likely)

Labradorite, calcium-sodium feldspar: (Ca,Na)(Al,Si)₄O₈

Yellow quartz crystal point, likely citrine-treated quartz

Quartz, SiO₂; probable heat-treated amethyst or iron-stained quartz

Tumbled pink quartz or rose quartz

Quartz, silicon dioxide (SiO₂); likely rose quartz, colored by trace elements and microscopic inclusions

Tumbled turquoise

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

Gravel / Limestone Fragment

Calcium Carbonate (CaCO3) / Fine-grained Sedimentary Rock

Fossil Shark Tooth

Carcharodon sp. (likely Otodus or similar Lamniformes order)

Cubic Zirconia

Zirconium dioxide (ZrO2)

Fossiliferous Chert (with Fossil Shells)

Silicon Dioxide (SiO2) with biogenic inclusions

Turquoise in Matrix

Hydrated copper aluminum phosphate, CuAl6(PO4)4(OH)8·4H2O

Pale greenish-yellow spodumene crystal (likely hiddenite or kunzite-family material)

Spodumene, LiAlSi₂O₆

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate quartz–feldspar aggregate; likely weathered granite (quartz, feldspar, minor iron oxides)

Tumbled tiger’s-eye

Quartz variety: fibrous chalcedony/quartz pseudomorph after crocidolite, SiO₂

Tumbled lapis lazuli

Lapis lazuli; mainly lazurite (Na₃Ca(Si₃Al₃)O₁₂S), with calcite and pyrite

Banded metamorphic rock, likely gneiss or schist

Quartz–feldspar–mica gneiss/schist; exact identification requires thin-section or tests

Polished druzy quartz specimen

Quartz (SiO₂), likely druzy quartz with possible blue chalcedony or inclusions

Weathered rhyolite (possibly porphyritic volcanic rock)

Rhyolite; chiefly quartz and alkali feldspar, with minor plagioclase and iron-bearing alteration minerals

Biotite-bearing granite or granitic gneiss

Quartz–feldspar–biotite rock; probable granite (locally gneissic)

Fine-grained gray rock, likely andesite or basalt

Aphanitic volcanic rock; probable basaltic-andesite (plagioclase ± pyroxene, minor iron oxides)

Vesicular basalt (scoriaceous basalt)

Basalt, predominantly plagioclase feldspar, pyroxene, and olivine; iron-oxide-rich alteration may cause the reddish-brown color

Tumbled black tourmaline

Schorl tourmaline, NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Weathered schist or gneiss cobble

Foliated silicate rock, likely mica schist or biotite gneiss

Rose quartz

Quartz, silicon dioxide (SiO₂), pink variety

Quartz-rich metamorphic rock, possibly mica schist

Muscovite–biotite schist with quartz; exact identification requires testing

Weathered conglomeratic volcanic rock

Likely basaltic volcanic breccia or agglomerate, with plagioclase, pyroxene, volcanic glass, and lithic fragments

Unidentified weathered stone, likely quartz-rich metamorphic rock

Possibly quartzite or vein quartz; exact identification is uncertain from the image

Quartzite

Quartzite, composed predominantly of recrystallized quartz (SiO₂)

Tumbled orbicular gabbro (likely oceanic gabbro)

Gabbro; chiefly plagioclase feldspar and pyroxene, with possible olivine, amphibole, and magnetite

Weathered porphyritic volcanic rock (likely andesite or basalt)

Fine-grained intermediate-to-mafic volcanic rock; likely andesite/basalt composed mainly of plagioclase, pyroxene, and possibly altered iron-bearing minerals

Serpentinite-bearing quartz vein rock

Serpentinite (antigorite/lizardite) with milky quartz; possible chlorite or epidote alteration

Iron-rich quartzite or weathered ironstone

Quartzite, chiefly SiO₂, with iron-oxide minerals such as hematite/goethite