Mixed: Igneous And Sedimentary

Graywacke sandstone (probable)

Lithic graywacke; composition commonly quartz, feldspar, lithic fragments, and clay-rich matrix

Tumbled jasper or chert pebble

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

River Rock (Glacial Cobbles)

Fluvial Alluvium (Mixed lithology including Quartzite, Basalt, and Granite)

Mixed rounded rock and mineral gravel

Predominantly weathered basalt, quartz-rich fragments, and iron-stained silicate rocks; exact species cannot be determined reliably from the image

Asphalt / Bituminous Aggregate

Bituminous mixture (Hydrocarbon-based sediment)

Pyrite-bearing sulfide specimen

Pyrite (FeS₂), possibly mixed with chalcopyrite or other iron sulfides

Rounded gray stone, likely weathered chert or quartz-rich river pebble

Chert (microcrystalline SiO₂), tentative

Chrysocolla

Hydrated copper phyllosilicate, Cu2-xAlx(H2-xSi2O5)(OH)4·n(H2O)

Pink Granite

Granite (Felsic Plutonic Igneous Rock)

Gneiss (likely garnet-bearing)

Banded orthogneiss/paragneiss; chiefly quartz, feldspar, biotite and amphibole, with possible garnet

Rounded conglomeratic river pebble

Polymict conglomerate (lithified gravel), composition uncertain from image

Polished labradorite-bearing rock

Labradorite, a calcium-rich plagioclase feldspar; likely mixed with quartz and mafic minerals

Pyrite in Quartz

FeS2 (Iron Pyrite) with SiO2 (Quartz)

Tumbled Agate

Silicon dioxide (SiO2)

Agate

Silicon dioxide (Chalcedony), SiO2

Petrified Wood and Mixed Rocks

Silicified Wood (SiO2)

Serpentinite

Serpentinite (composed mainly of serpentine group minerals: (Mg,Fe)3Si2O5(OH)4)

Botryoidal hematite (specular/earthy hematite)

Hematite, Fe₂O₃

Agate Bookend / Quartz Geode

Silicon Dioxide (SiO2)

Graywacke (River Cobble)

Graywacke (Lithic Sandstone)

Yellow Chert (Chert / Jasper)

Silicon Dioxide (SiO2 / Microcrystalline Quartz)

Conglomeratic sandstone or breccia

Lithic arkose / polymictic conglomeratic sandstone

Mixed pebble collection, including likely flint, quartzite, and fossil material

Varied silicate rocks; visible specimen may include chert (microcrystalline SiO₂), quartzite, and a possible fossil

Agate Nodule

Silicon Dioxide (Quartz/Chalcedony), SiO2

Pegmatite with Quartz and Feldspar

Intrusive Igneous Rock

Mixed tumbled gemstone chips

Polychrome jasper, quartz/chalcedony, feldspar, and other silicate fragments (exact identification requires testing)

Mixed Quartz and River Pebbles (Stone Collection)

Mixed assortment containing mainly Silicon Dioxide (SiO2)

Pink Granite

Felsic Plutonic Rock (Granite)

Weathered granite pebble

Granite, predominantly quartz–feldspar–mica aggregate

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)

Peacock Ore

Bornite (Cu5FeS4)

Mixed gravel and mineral fragments

Polymictic unconsolidated sediment; likely quartz, feldspar, chert, mica, and lithic fragments

Mixed tumbled stones, likely rose quartz and purple quartz/amethyst

Quartz (SiO₂), including amethyst and probable rose quartz; exact identification is uncertain from the blurred image

Polished pink-and-gray stone, possibly granite or rhyolite

Probable felsic igneous rock; likely quartz–feldspar–mica aggregate, but exact identification is uncertain from the image

Tumbled orbicular granite

Granite, commonly biotite–quartz–feldspar granite with orbicular or mafic enclaves

Epidote in Granite Gneiss

Epidote bearing Orthogneiss (Ca2(Al,Fe)3(SiO4)3(OH))

Red porphyritic volcanic rock, likely rhyolite or andesite

Porphyritic rhyolite–andesite; predominantly quartz/feldspar with iron-oxide staining

Mixed rounded river pebbles, likely basalt and granite

Basalt (fine-grained mafic rock) and granite/granitoid (quartz–feldspar rock)

Fuchsite Schist

Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2) in Schist

Pea Gravel / River Gravel

Unconsolidated Clastic Sedimentary Aggregate

Likely quartz-bearing metamorphic pebble

Indeterminate; probable quartzite or quartz-rich gneiss with dark mica/amphibole

Weathered metallic sulfide-bearing rock, possibly pyrite-rich ore

Tentatively pyrite (FeS₂) with iron oxides and host rock; exact identification requires testing