Uncertain

Mixed rock and mineral collection

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

Quartz-rich metamorphic rock, likely mica schist or quartzite

Quartz (SiO₂) with mica, feldspar, and possibly iron-oxide staining

Weathered sandstone or quartz-rich metasedimentary pebble

Likely quartz arenite (sandstone), possibly weakly metamorphosed; predominantly SiO₂ quartz with feldspar and iron-oxide cement

Amethyst (rough crystal cluster)

Quartz, SiO₂; purple coloration commonly caused by trace iron and natural irradiation

Tumbled dark stone, likely basalt or basaltic rock

Fine-grained mafic volcanic rock; commonly basalt, composed chiefly of plagioclase and pyroxene with possible olivine and iron oxides

Uncertain dark, weathered rock fragment

Possibly basalt or a dark mafic volcanic rock; identification is limited by blur and lighting

Uncertain pale mineral/rock fragment

Indeterminate; possibly calcite-rich material or a light-colored carbonate rock

Uncertain small tan mineral/rock fragment

Indeterminate from image; possibly feldspar-rich rock or calcite

Likely dyed pink quartz or agate fragment

Quartz, SiO₂ (identity uncertain from the image)

Tumbled chalcedony (likely yellow/brown jasper or agate)

Microcrystalline quartz, SiO₂ (chalcedony; variety uncertain)

Possible basalt or iron-rich slag

Basalt (tentative; identification uncertain from image)

Dark rounded stone, likely basalt or weathered mafic rock

Basalt (probable; identification uncertain from photograph)

Tumbled yellow quartz (likely citrine or yellow chalcedony)

Quartz, SiO₂; variety uncertain from image

Likely weathered iron-rich stone

Uncertain; possibly limonite/goethite-bearing rock

Polished orbicular jasper (likely ocean jasper)

Silicified microcrystalline quartz (SiO₂), commonly called orbicular jasper or ocean jasper

Rounded gray pebble, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; commonly basalt (plagioclase ± pyroxene/olivine)

Quartz-rich pebble (likely milky quartz)

Quartz, SiO₂

Milky quartz-bearing rock, possibly quartzite

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

Tumbled carnelian (likely)

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

Polished agate (likely moss agate)

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

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

Nickel–iron meteorite (likely weathered iron meteorite)

Fe–Ni alloy, chiefly kamacite and taenite

Tumbled amber-colored chalcedony (likely carnelian)

Microcrystalline quartz, SiO₂; orange-red variety commonly termed carnelian

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

Polished agate or chalcedony cabochon

Microcrystalline quartz (SiO₂), likely pale chalcedony/agate

Tumbled green aventurine or quartzite pebble

Quartz (SiO₂), likely aventurine-bearing quartzite

Black polished stone, likely black tourmaline or obsidian

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