Mineralological Specimen

Rock crystal (clear quartz), likely rough or lightly polished

Quartz — silicon dioxide (SiO₂)

Weathered iron-rich volcanic rock (probable basalt or andesite)

Altered basalt/andesite, composed chiefly of plagioclase, pyroxene, and iron oxides/hydroxides

Likely weathered iron-rich pebble (brown sandstone or ironstone)

Indeterminate ferruginous sandstone/ironstone; commonly quartz (SiO₂) with iron oxides such as goethite and hematite

Gold-bearing quartz vein rock

Quartz (SiO₂) with probable native gold and iron-oxide minerals

Brecciated quartz vein rock

Quartz (SiO₂), with iron-oxide staining and likely feldspar/carbonate gangue

Fossiliferous limestone with possible ammonite or shell impressions

Calcitic limestone, chiefly CaCO₃; fossils may include ammonoids or bivalves

Weathered granite or granitic gneiss pebble

Granite, chiefly quartz (SiO₂), feldspar, and biotite/hornblende; exact identification is uncertain from the image

Druzy Quartz Geode (with Chalcedony)

Silicon Dioxide (SiO2)

Quartz on Host Rock

Silicon Dioxide (SiO2)

Quartz (Smoky/Grey variety)

Silicon Dioxide (SiO2)

Chert / Green Jasper

Silicon Dioxide (SiO2)

Jasper with Chalcedony

Silicon Dioxide (SiO2)

Yellow Quartzite (River Pebble)

Quartzite (SiO2)

Chalcedony with Druzy Quartz Geode

Silicon Dioxide (SiO2)

Jasper

Microcrystalline Quartz (SiO2)

N/A (Non-Geological Specimen)

Pyrite in Matrix

Iron Sulfide (FeS2)

Chert (Sea-worn Pebble)

Microcrystalline Quartz (SiO2)

Chalcedony (Agate/Jasper mix)

Cryptocrystalline Quartz (SiO2)

Likely muscovite-bearing mica schist

Mica schist, composed mainly of quartz and mica (muscovite and/or biotite)

Quartz (Chalcedony/Agate)

Silicon Dioxide (SiO2)

Fossiliferous Limestone with Crinoid Stem

Sedimentary Rock with Echinodermata fossil fragment

Concretion

Septarian Concretion (Fragmentary)

Weathered quartz-bearing rock, possibly granitic gneiss

Quartz–feldspar–mica aggregate; exact identification requires testing

Small brown mineral specimen, possibly mica-bearing rock

Unidentified from the image; exact mineral species cannot be determined at this scale

Sandstone (Quartzite texture)

Arenite (SiO2 secondary)

Coarse granite (likely weathered biotite granite)

Granite; quartz + feldspar + biotite/hornblende, approximate composition 20–60% quartz and abundant K-feldspar/plagioclase

Yellow tumbled stone, likely calcite

Calcite (CaCO₃), possibly yellow or honey calcite

Fossiliferous limestone with a shell fossil

Bioclastic limestone containing a probable bivalve or brachiopod fossil; exact identification is not possible from the image alone.

Likely hematite-bearing ironstone

Hematite (Fe₂O₃), possibly mixed with other iron oxides and host rock

Mixed gravel and small stones

Unsorted gravel; individual clasts are not identifiable from the image

Small brown rock fragment; exact identification uncertain

Unidentified fine-grained lithic fragment

Quartz-rich stone, possibly aventurine quartz or quartzite

Quartz (SiO₂), likely massive or microcrystalline; exact identification requires testing

Polished picture jasper

Silicified microcrystalline quartz (chalcedony), commonly called picture jasper

Small polished dark mineral or gemstone fragment

Indeterminate; possibly smoky quartz, obsidian, or dark tourmaline

Granite Cobble

Phaneritic Felsic Igneous Rock

Pegmatite with Schorl (Black Tourmaline) and Mica

Pegmatite (complex association of NaAlSi3O8, NaFe3Al6(BO3)3Si6O18(OH)4, and KAl2(AlSi3O10)(OH,F)2)

Reddish-brown, iron-stained rock fragment

Indeterminate; possibly weathered porphyritic volcanic rock

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Labradorite

Labradorite ((Ca, Na)(Al, Si)4O8)

Carnelian Agate

Silicon Dioxide (SiO2) - Variety: Chalcedony

Greenstone, likely altered basalt

Metabasalt (chlorite–actinolite–epidote assemblage), likely greenschist-facies greenstone