Uncertain

Likely coal (possibly anthracite)

Coal, a carbon-rich sedimentary rock; anthracite is predominantly carbon

Mixed rock and mineral collection

Mixed lithologies; likely quartz, feldspar, basalt, granite, chert, sandstone, and metamorphic rocks

Orange chalcedony (possibly carnelian)

Chalcedony, microcrystalline quartz (SiO₂); orange-red varieties are called carnelian

Likely muscovite mica

Muscovite, KAl₂(AlSi₃O₁₀)(OH)₂

Weathered quartz-rich river pebble

Quartz-rich lithic clast, likely quartzite or quartz-veined rock; exact identification requires examination

Small polished agate (likely banded chalcedony)

Chalcedony, microcrystalline quartz (SiO₂)

Lichen-covered metamorphic rock, likely gneiss

Quartz–feldspar–mica gneiss (identification tentative from the surface image)

Milky quartz pebble

Quartz, silicon dioxide (SiO₂)

Polished agate (likely moss agate)

Microcrystalline quartz, SiO₂ (chalcedony); possible moss-like inclusions

Tumbled carnelian (likely)

Chalcedony, microcrystalline quartz (SiO₂), iron-oxide colored

Honey calcite crystal cluster

Calcite (CaCO₃)

Quartz-rich pebble (likely milky quartz)

Quartz, SiO₂

Milky quartz-bearing rock, possibly quartzite

Quartz (SiO₂), likely in a quartzite or quartz-rich vein

Rounded yellow-brown chert or jasper pebble

Microcrystalline quartz (SiO₂), likely iron-stained chert/jasper

Weathered quartz-rich rock, likely granite or granitic gneiss

Granite–gneissic felsic rock; chiefly quartz (SiO₂), feldspar, and minor mica/biotite

Quartz-rich granitic fragment

Likely granite or granitic pegmatite; chiefly quartz (SiO₂) with feldspar and possibly mica

Polished serpentinite (likely)

Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), commonly with magnetite and chromite

Quartz-rich breccia or conglomerate

Siliciclastic breccia/conglomerate, likely containing quartz and iron-oxide-stained rock fragments

Smoky quartz crystal cluster

Quartz, silicon dioxide (SiO₂), likely smoky variety with possible feldspar or matrix inclusions

Tumbled amethyst

Quartz, purple variety; silicon dioxide (SiO₂), colored mainly by iron-related defects

Milky quartz (likely quartz-rich specimen)

Quartz, silicon dioxide (SiO₂)

Likely tumbled lepidolite-bearing mica schist

Lepidolite-rich mica schist; chiefly lepidolite/muscovite mica, quartz, and possibly feldspar

Rounded metallic-looking pebble, likely iron-rich rock or slag

Uncertain; possible limonite/goethite-rich ironstone, hematite-bearing material, or industrial slag

Serpentine-rich rock (likely serpentinite)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, carbonate, or talc

Tumbled pale stone, likely quartz-rich rock or calcite

Uncertain from image; possibilities include microcrystalline quartz (SiO₂) or calcite (CaCO₃)

Dark igneous rock, likely basalt

Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase and pyroxene, commonly with olivine

Hessonite garnet in matrix

Hessonite, a grossular garnet; Ca₃Al₂(SiO₄)₃

Polished brecciated jasper

Microcrystalline quartz (SiO₂), with iron-oxide staining

Diamond (set in an ornate ring)

Diamond, crystalline carbon (C)

Tumbled orange-brown jasper

Jasper, an opaque, iron-rich variety of microcrystalline quartz (SiO₂)

Polished agate or chalcedony cabochon

Microcrystalline quartz (SiO₂), likely pale chalcedony/agate

Tumbled green aventurine or quartzite pebble

Quartz (SiO₂), likely aventurine-bearing quartzite

Tumbled granite

Granite, a coarse-grained felsic intrusive igneous rock

Iron-stained quartz-rich rock (likely ferruginous quartzite)

Quartz-rich ferruginous rock, probably quartzite with iron-oxide staining (SiO₂ with hematite/goethite)

Polished brecciated jasper (likely)

Brecciated jasper, an opaque microcrystalline quartz (SiO₂) with contrasting silica-rich fragments and matrix

Polished banded agate (likely petrified wood)

Microcrystalline quartz (SiO₂); possibly silicified wood

Red aventurine quartzite (likely)

Quartzite; predominantly microcrystalline quartz (SiO₂) with iron-oxide and feldspar impurities

Black polished stone, likely black tourmaline or obsidian

Possibly schorl tourmaline, NaFe3Al6(BO3)3Si6O18(OH)4, or volcanic glass (obsidian), SiO2-rich

Milky quartz with possible mica or feldspar inclusions

Quartz (SiO₂), likely with minor inclusions

Likely rough garnet-bearing metamorphic rock

Garnet schist or garnet amphibolite; reddish areas may be almandine garnet (Fe₃Al₂Si₃O₁₂)

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), with possible feldspar, mica, and iron-oxide staining

Weathered granite or granodiorite boulder

Granite–granodiorite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende