Mixed

Snowflake Obsidian (possibly mixed with Jasper or other matrix)

Obsidian with Cristobalite inclusions

Mixed gemstone jewelry collection

Likely amethyst, rose quartz or pink tourmaline, smoky quartz, and dark tourmaline/onyx; exact identifications are uncertain from the image

Mixed rounded river gravel

Polymictic alluvial gravel; likely mixtures of quartzite, granite, basalt, sandstone, and other silicate rocks

Mixed landscaping gravel with a pink granite cobble

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

Mixed polished river pebbles, predominantly quartzite and quartz

Quartzite (SiO₂), quartz (SiO₂), with possible feldspar-rich and iron-stained lithologies

Mixed mineral and crystal specimens

Likely quartz varieties and other common minerals; exact identification is uncertain from the image

Mixed rock and mineral specimens

Predominantly quartz-rich rocks, with a possible malachite-bearing specimen; exact identification is uncertain from the image

Quartz and Mixed Sedimentary Rocks

Silicon Dioxide (SiO2) mixed with various clastic sedimentary lithologies

River Cobble (Mixed Lithology)

Clastic Sedimentary Rock (Silicified Siltstone or Wacke)

Mixed Mineral Collection (with Quartz, Beryl, and host rock)

Silicon Dioxide (Quartz), Be3Al2Si6O18 (Beryl), and associated Schist/Pegmatite

Mixed collection of natural stones

Several unidentified lithologies, likely including basalt, granite, quartzite, sandstone, and weathered metamorphic rocks

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.

Mixed Mineral and Rock Collection

Mixed geological specimens (Quartz, Amethyst, Rose Quartz, Jasper, Epidote, Chert)

Mixed River Pebbles and Jasper

Siliciclastic sediment and microcrystalline quartz

Tumbled mixed mineral specimens, likely quartz-rich rocks

Predominantly quartz (SiO₂), with possible jasper, agate, feldspar, and iron-oxide minerals

Chrysocolla-bearing copper ore (tentative)

Chrysocolla, a hydrated copper silicate; commonly intergrown with quartz and/or other copper minerals

Weathered granitic rock fragment

Likely granite or granodiorite; quartz–feldspar–mica aggregate

Likely quartz-bearing metamorphic pebble

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

Granite Cobble

Phaneritic Felsic Igneous Rock (Granite)

Ptygmatic Migmatite

Migmatite (consisting of Neosome and Paleosome fractions)

Tourmaline crystals

Elbaite tourmaline; complex boron silicate, commonly approximated as Na(Li,Al)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

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

Chert (microcrystalline SiO₂), tentative

Chrysocolla Chalcedony

Hydrated Copper Phyllosilicate (Cu,Al)2H2Si2O5(OH)4 + SiO2

Epidote in Granite Gneiss

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

Mookaite Jasper

Silicon Dioxide with Iron Oxide impurities (SiO2)

Yellow Jasper

Silicon Dioxide (SiO2) with hydrated iron oxide impurities (Goethite)

Fossiliferous Limestone

Limestone (CaCO3 with Limonite/Goethite staining)

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

Sandstone (lithic wake/graywacke variety)

Arenite/Greywacke (SiO2 with lithic fragments)

Fuchsite Schist

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

Mahogany Obsidian

Volcanic glass containing Magnetite/Hematite

Pink and Green Tourmaline (Tumbled)

Elbaite (Na(Li,Al)3Al6(BO3)3Si6O18(OH)4)

Weathered, foliated metamorphic rock (likely schist)

Mica schist, composition uncertain from the photograph

Milky quartz (likely quartz-rich rock fragment)

Quartz, silicon dioxide (SiO₂)

Quartz-rich rock or quartz specimen

Quartz (SiO₂), likely massive quartz or quartz-bearing host rock

Graphite-bearing schist (probable)

Graphite–quartz–mica schist; chiefly graphite (C), quartz (SiO₂), and mica

Rose Quartz and Pegmatite

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Conglomerate

Conglomerate (clastic sedimentary rock)

Chrysocolla

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

Chrysocolla

Hydrated copper silicates (Cu,Al)2H2Si2O5(OH)4·nH2O

Weathered iron-stained rock fragment

Uncertain from the image; likely an iron-oxide-stained, quartz- and feldspar-bearing rock