Uncertain

Metallic sulfide ore, likely pyrite-bearing rock

Pyrite (FeS₂), possibly with marcasite or other sulfides

Weathered amphibolite or mafic metamorphic rock

Amphibolite; chiefly hornblende amphibole and plagioclase feldspar

Polished turquoise-like stone

Likely turquoise, hydrated copper–aluminum phosphate: CuAl₆(PO₄)₄(OH)₈·4H₂O; identification is uncertain from the photo

Likely weathered iron-rich stone or concretion

Indeterminate; possibly ferruginous sandstone, ironstone, or a weathered sedimentary concretion

Amethyst-bearing quartz geode or crystal cluster

Quartz, SiO₂; purple coloration from trace iron and irradiation

Fossil-bearing limestone slab

Bioclastic limestone, likely containing brachiopod or bivalve impressions

Yellow quartz-bearing rock, possibly sulfur-stained quartz or calcite

Indeterminate; likely quartz (SiO₂) and/or calcite (CaCO₃) with yellow iron/sulfur staining

Green aventurine (likely)

Quartz variety; silicon dioxide (SiO₂), commonly colored by fuchsite mica or other inclusions

Green aventurine bead

Quartz (SiO₂), usually quartzite containing fuchsite mica

Blue gemstone ring, likely sapphire

Corundum, Al₂O₃ (probable blue sapphire); surrounding stones may be diamonds or simulants

Red-brown granite or granitic gneiss fragments

Felsic granitoid, chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende

Likely basaltic rock

Fine-grained basalt, possibly dolerite/diabase

Fine-grained dark igneous rock, likely basalt

Basalt; predominantly plagioclase feldspar and pyroxene, commonly with minor olivine and iron-titanium oxides

Weathered granite or granitic gneiss cobble

Granite; primarily quartz, feldspar, and mica

Polished black stone, likely black obsidian

Obsidian (volcanic glass), chiefly SiO₂

Red-orange jasper pebble (tentative)

Microcrystalline quartz, SiO₂, colored mainly by iron oxides

Metamorphic schist (probable mica schist)

Mica schist, dominated by quartz, feldspar, biotite/muscovite, and possibly garnet

Rose quartz (likely)

Quartz, silicon dioxide (SiO₂), commonly massive rather than visibly crystalline

Black tourmaline (likely schorl)

Schorl, NaFe3Al6(BO3)3Si6O18(OH)4

Vesicular volcanic rock (likely pumice or scoria)

Pumice/scoria; predominantly volcanic glass and feldspar-rich silicate material

Iron-rich goethite/limonite specimen

Goethite, α-FeO(OH), commonly mixed with limonite and other iron oxides

Serpentine-rich metamorphic rock

Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite and carbonates

Likely smoky quartz pendant

Smoky quartz, silicon dioxide (SiO₂), quartz variety colored by irradiation-related defects

Amber (rough fossilized resin)

Amber; predominantly polymerized fossil plant resin, commonly succinite (C₁₀H₁₆O)

Likely banded obsidian or dark volcanic glass

Obsidian, predominantly rhyolitic volcanic glass (SiO₂-rich), possibly with devitrified bands and phenocrysts

Rounded orange-brown pebble (likely iron-stained quartzite)

Quartz-rich quartzite; exact identification is uncertain from the image

White tumbled stone (possibly milky quartz)

Likely quartz, SiO₂; exact identification is uncertain from the image

Greenish metamorphic rock (possibly chlorite schist)

Chlorite-rich schist; exact identification is uncertain from the image

Tiny pale-green mineral fragment

Likely chrysoprase or green quartz; identification is uncertain from the photograph

Small polished translucent gemstone, possibly rose quartz or pink fluorite

Uncertain from image; likely quartz (SiO₂) or fluorite (CaF₂)

Rounded tan pebble, possibly quartzite

Likely quartz-rich quartzite; identification is uncertain from the photo

White beach pebbles, likely milky quartz

Probably quartz (SiO₂); exact identification is uncertain from the image

Polished/tumbled pale-yellow stone, possibly calcite

Likely calcite (CaCO₃); identification is uncertain from the image alone

Weathered quartz-rich rock, possibly quartzite or quartz vein fragment

Quartzite (mostly microcrystalline SiO₂), identification uncertain from image

Polished black-and-white banded agate (likely dyed or painted)

Chalcedony (microcrystalline quartz), SiO₂; exact banding variety uncertain

Likely fluorite or another fluorescent mineral

Uncertain from the ultraviolet-tinted image; possible fluorite (CaF₂)

Likely green fluorite or calcite specimen

Fluorite (CaF₂) or calcite (CaCO₃); identification is uncertain from the image

Likely raw quartz-bearing stone, possibly greenish quartz or calcite

Uncertain from photograph; possible quartz (SiO₂) or calcite (CaCO₃)

Polished brown pebble, likely jasper or iron-stained quartzite

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

Polished/tumbled light-colored stone, possibly quartzite or marble

Uncertain; likely quartzite (mostly SiO₂) or calcite marble (CaCO₃)

Blue-gray metamorphic rock fragment

Likely slate or phyllite; exact identification is uncertain from the photograph

Weathered mafic rock fragment

Likely basalt or volcanic breccia; identification is uncertain from the photograph