Sedimentary And Igneous (Mixed)

Weathered polymictic rock fragment, likely granite-rich conglomerate

Indeterminate mixed lithology; apparent granitic clasts containing quartz, feldspar, and dark mafic minerals

Graphite

Graphite (Native Carbon, C)

Mixed rock and mineral specimens

Multiple unidentified silicate rocks and minerals; likely quartz-bearing material, feldspar, mica, and iron-oxide-bearing stones

Snowflake Obsidian (possibly mixed with Jasper or other matrix)

Obsidian with Cristobalite inclusions

Mixed landscaping gravel with a pink granite cobble

Primarily granite (quartz, alkali feldspar, plagioclase, biotite); mixed pebble assemblage

Mixed rounded stream pebbles

Most appear to be granitic and mafic igneous rocks, including granite, gneiss, basalt, and possibly quartzite; exact identification is uncertain from the image.

Pyrite-bearing sulfide specimen (likely pyrite)

Pyrite, FeS₂; possibly mixed with pyrrhotite or chalcopyrite

Tumbled quartz-rich stone, possibly granite or rhyolite

Likely quartz (SiO₂) with feldspar and minor mica or other inclusions

Crushed granite aggregate

Granite, a coarse-grained felsic intrusive igneous rock composed mainly of quartz, alkali feldspar, plagioclase, and minor mica/amphibole

Tumbled granite or granitic gneiss pebble

Granite/granitic gneiss, chiefly quartz, feldspar, and dark biotite or amphibole

Granite

Granite; primarily quartz, alkali feldspar, plagioclase, and biotite/hornblende

Mixed Tumbled Gemstones (Agate, Aventurine, Pyrite, etc.)

Multiple (principally Silicon Dioxide SiO2 and Iron Disulfide FeS2)

Likely gray granite fragment

Granite, composed mainly of quartz, feldspar, and mica

Concrete

Anthropogenic Sedimentary Rock (Hydrated Calcium Silicate)

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

Weathered polymictic gravel/conglomeratic rock

Polymictic conglomerate or poorly lithified alluvial gravel; chiefly quartz, feldspar, mica, and dark lithic fragments

Mixed rounded gravel and weathered rock fragments

Polymictic alluvial or glacial gravel; composition appears to include basaltic, quartz-rich, and feldspathic clasts

Milky quartz (likely quartz-rich rock fragment)

Quartz, silicon dioxide (SiO₂)

Biotite granite (likely weathered granite)

Granite; quartz + feldspar + biotite, with accessory dark minerals

Rounded conglomeratic river pebble

Polymict conglomerate (lithified gravel), composition uncertain from image

Pink Granite

Phaneritic Plutonic Felsic Rock (K-feldspar rich)

Botryoidal hematite (specular/earthy hematite)

Hematite, Fe₂O₃

Asphalt / Bituminous Aggregate

Bituminous mixture (Hydrocarbon-based sediment)

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

Polished labradorite-bearing rock

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

Graywacke (River Cobble)

Graywacke (Lithic Sandstone)

Yellow Chert (Chert / Jasper)

Silicon Dioxide (SiO2 / Microcrystalline Quartz)

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

Chert (microcrystalline SiO₂), tentative

Conglomeratic sandstone or breccia

Lithic arkose / polymictic conglomeratic sandstone

Chrysocolla

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

Mixed tumbled quartz specimens

Quartz, silicon dioxide (SiO₂), including rose quartz and milky/included varieties

Pyrite in Quartz

FeS2 (Iron Pyrite) with SiO2 (Quartz)

Gneiss (likely garnet-bearing)

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

Pink Granite

Granite (Felsic Plutonic Igneous Rock)

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

River Rock (Glacial Cobbles)

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

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

Pyrite-bearing sulfide specimen

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

Pink Granite

Felsic Plutonic Rock (Granite)

Weathered granite pebble

Granite, predominantly quartz–feldspar–mica aggregate