All rocks & minerals

Red jasper (likely)

Jasper, an opaque variety of microcrystalline quartz (SiO₂), colored red by iron oxides

Jasper Pebble

Microcrystalline Quartz (SiO2)

Quartz-rich pegmatite

Granitic pegmatite composed mainly of quartz, with probable feldspar and mica

Pyrite (fool’s gold)

Pyrite, FeS₂ (iron disulfide)

Flint (chert)

Microcrystalline quartz (SiO₂), a variety of chert

Chert (Jasper Pebble)

Microcrystalline Quartz (SiO2)

Black volcanic rock (possibly obsidian or basalt)

Indeterminate from the image; candidates include volcanic glass (obsidian, SiO₂-rich) or basalt (plagioclase–pyroxene-rich)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Rounded brown pebble

Unidentified lithic pebble; composition cannot be determined from the image

Polished obsidian (likely snowflake obsidian)

Volcanic glass, chiefly rhyolitic; snowflake patterns are cristobalite/spherulites in obsidian

Obsidian (volcanic glass)

Obsidian; predominantly silica-rich volcanic glass, commonly rhyolitic in composition

Milky quartz

Quartz (silicon dioxide, SiO₂)

Likely weathered quartz-rich rock with iron staining

Indeterminate from the photograph; possibly quartzite or quartz-rich vein material with iron-oxide coatings

Petrified wood (likely iron-stained)

Silicified fossil wood; commonly quartz/chalcedony (SiO₂) replacing wood

Likely weathered metallic meteorite fragment

Unconfirmed; possibly an iron-nickel meteorite, mainly kamacite and taenite

Weathered granite or granitic gneiss

Quartz–feldspar–biotite granitoid; exact identification requires close examination

Likely greenstone (metamorphosed mafic rock)

Greenstone; commonly chlorite–actinolite–epidote–albite assemblage

Red sandstone

Quartz-rich sandstone, commonly iron-oxide-cemented (SiO₂ with hematite/goethite)

Red sandstone with pale weathered surface

Iron-oxide-stained quartz arenite (sandstone)

Likely rough green aventurine

Quartz (SiO₂), with green coloration likely from mica or other inclusions

Red sandstone

Quartz-rich sandstone, commonly composed of quartz grains cemented by iron oxides

Pyrite-bearing rock in reddish shale

Iron sulfide (pyrite, FeS₂) in iron-rich shale or mudstone

Orange chalcedony (possibly carnelian)

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

Milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Opal-bearing rock (possible common opal in host rock)

Hydrated amorphous silica, SiO₂·nH₂O, occurring in a pale host rock

Quartz-veined dark volcanic rock (likely basalt)

Basalt with a quartz-rich vein; exact identification requires testing

Rounded quartz-rich pebble

Likely quartzite (metamorphosed quartz sandstone), composition predominantly quartz (SiO₂)

Milky quartz

Quartz (SiO₂), commonly called milky quartz

Likely galena (lead sulfide)

Galena, PbS

Gold-bearing placer gravel (possible gold flakes)

Unconsolidated alluvial sediment containing quartz, lithic fragments, and possibly native gold (Au)

Biotite–muscovite schist (mica schist)

Mica schist, likely quartz–feldspar–biotite ± muscovite; exact minerals cannot be confirmed from the photo

Likely native silver-bearing ore or metallic slag-like specimen

Uncertain from the photograph; possible native silver (Ag), but identification requires testing

Yellow calcite

Calcite (CaCO₃)

Honey calcite (yellow calcite)

Calcite, CaCO₃

Likely native silver

Native silver (Ag); identification is provisional from the photo

Tumbled orange calcite

Calcite (CaCO₃)

Muscovite-rich mica schist

Mica schist, chiefly muscovite [KAl₂(AlSi₃O₁₀)(OH)₂], possibly with quartz and feldspar

Honey-colored calcite

Calcite (CaCO₃)

Gypsum (selenite/alabaster variety)

Gypsum, CaSO₄·2H₂O

Weathered mica-rich schist

Mica schist, likely muscovite–quartz schist

Likely gray chert (flint) pebble

Microcrystalline quartz (SiO₂), commonly called chert or flint

Possible iron meteorite

Native iron–nickel alloy, typically kamacite and taenite; identification is uncertain from the image alone