Sedimentary And Igneous (Mixed)

Mixed rock fragments, likely basalt and weathered granite

Probable mafic volcanic rock (basalt) with granitoid fragments; exact identification is uncertain from the image

Mixed rounded cobbles, likely granite and weathered volcanic rock

Granite and probable andesite/basalt clasts; exact identification is uncertain from the photograph

Beach cobbles, predominantly basalt with vesicular volcanic fragments

Basalt (mafic volcanic rock), with possible altered basalt and minor feldspar/quartz-bearing pebbles

Concrete

Anthropogenic Sedimentary Rock (Hydrated Calcium Silicate)

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

Chert (microcrystalline SiO₂), tentative

Pegmatite with Quartz and Feldspar

Intrusive Igneous Rock

Mixed Rock and Mineral Specimen Set

Multiple (Quartz, Chert, Shale)

Mixed Quartz and River Pebbles (Stone Collection)

Mixed assortment containing mainly Silicon Dioxide (SiO2)

Milky quartz (likely quartz-rich rock fragment)

Quartz, silicon dioxide (SiO₂)

Faceted gemstones, likely mixed small sapphires or spinel

Corundum (Al₂O₃) or spinel (MgAl₂O₄); exact identification requires testing

Pink Granite

Granite (Felsic Plutonic Igneous Rock)

Rounded conglomeratic river pebble

Polymict conglomerate (lithified gravel), composition uncertain from image

Graywacke (River Cobble)

Graywacke (Lithic Sandstone)

Yellow Chert (Chert / Jasper)

Silicon Dioxide (SiO2 / Microcrystalline Quartz)

Tumbled orbicular granite

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

Polished brecciated jasper bracelet

Jasper, microcrystalline quartz (SiO₂), commonly with hematite and iron-oxide inclusions

Red porphyritic volcanic rock, likely rhyolite or andesite

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

Pyrite in Quartz

FeS2 (Iron Pyrite) with SiO2 (Quartz)

Botryoidal hematite (specular/earthy hematite)

Hematite, Fe₂O₃

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

Conglomeratic sandstone or breccia

Lithic arkose / polymictic conglomeratic sandstone

Chrysocolla

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

Mixed tumbled gemstone chips

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

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

Mixed tumbled gemstone and mineral lot

Primarily quartz varieties (SiO₂), feldspar, beryl/chalcedony, and other unidentified silicate minerals

Mixed collection of polished pebbles, including probable fossiliferous limestone

Unidentified sedimentary rocks; the gray pebble with circular fossils may be bioclastic limestone

Rounded river pebbles (mixed lithologies)

Water-worn clasts; individual stones cannot be identified precisely from the image

Mixed gravel and mineral fragments

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

Mixed limestone and sandstone specimens

Mostly calcitic limestone (CaCO₃), with possible quartz-rich sandstone and iron-oxide staining

Mixed gravelly conglomeratic road aggregate

Polymictic clast-supported conglomerate or fill; composition varies, commonly quartz, feldspar, basalt, and weathered rock fragments

Mixed river gravel, prominently iron-stained chert/jasper

Microcrystalline quartz (SiO₂), chiefly chert/jasper with iron-oxide staining; mixed clasts may include quartzite and other silicates

Jasper and Mixed River Pebbles

Microcrystalline Quartz (Chalcedony / Jasper)

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

Mixed quartz gemstone bead bracelet

Quartz, silicon dioxide (SiO₂), in varieties including smoky quartz, amethyst, rutilated quartz, and possibly tourmalinated quartz

Serpentinite

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

Gneiss (likely garnet-bearing)

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

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)

Epidote in Granite Gneiss

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

Pea Gravel / River Gravel

Unconsolidated Clastic Sedimentary Aggregate