Igneous, Metamorphic, And Sedimentary (Mixed Assemblage)

Quartz-rich rock or quartz specimen

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

Silver-colored mica schist

Muscovite–quartz schist, possibly with biotite

Weathered metamorphic rock, likely gneiss or schist

Indeterminate foliated silicate rock; commonly quartz–feldspar–mica assemblage

Arkosic Sandstone (or Conglomeritic Sandstone fragment)

Arkose (rich in feldspar)

River Pebbles and Quartz

Mixed Igneous, Sedimentary, and Metamorphic Rocks (Silicon Dioxide SiO2 dominant)

Aventurine (Green Quartz)

Silicon Dioxide (SiO2) with inclusions of Fuchsite (Mica)

Mixed river stones; foreground likely sandstone

Quartz-rich sandstone, with associated rounded quartzite/chert and other cobbles

Tumbled quartz-rich stone, possibly milky quartz or calcite

Quartz (SiO₂) or calcite (CaCO₃); exact identification requires testing

Conglomeratic concrete or asphalt aggregate surface with dark bituminous chunks

Polymictic gravel aggregate; dark pieces likely bitumen/asphalt, not a natural rock

Mixed tumbled stones

Mixed aggregate of quartz, chalcedony, jasper, feldspar, and other common silicate minerals

Mixed rock and mineral specimen collection

Varied silicate, carbonate, and oxide minerals; individual identification is not possible from this group photograph

Migmatite

Migmatite (Mixed metamorphic-igneous rock)

Mixed Rock Collection

Polylithic Geological Specimen Mix

Mixed collection of natural stones

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

Mixed rock and mineral specimen collection

Multiple species, likely quartz (SiO₂), calcite (CaCO₃), feldspar, chert, and assorted volcanic/sedimentary rocks

Decorative polished pebbles

Likely mixed quartz-rich lithologies, including quartzite, jasper, and/or basalt

Beach Pebbles and Quartz Aggregates

Quartz pebbles and biogenic fragments (SiO2, CaCO3)

Banded River Cobble with Mafic Dike

Hydrothermally altered Graywacke or Sandstone with Mafic Intrusion

Mixed river stones and gravel

Polymictic alluvial clasts; individual pieces may include quartzite, granite, basalt, sandstone, limestone, and slate

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Polished banded gneiss

Gneiss, typically quartz–feldspar–mica assemblage

Assorted Decorative Tumbled Stones (Quartz, Sodalite, Aventurine, Calcite)

Mixed Silicates and Carbonates (SiO2, Na8(Al6Si6O24)Cl2, CaCO3)

Quartz-rich granitic cobble

Granite or granitic gneiss; primarily quartz, feldspar, and mica

Mixed River Stones and Minerals

Mixed Silica-rich Stones (Quartz, Agate, Jasper, Sandstone, Dalmation Stone)

Banded gneiss

Gneiss; typically quartz–feldspar–mica assemblage

Mixed Rock and Mineral Collection

Various geological specimens

Venetian Gold Granite

Phaneritic Felsic Igneous Rock (Granite)

Mixed polished river stones

Likely quartz, quartzite, chert/jasper, and possibly limestone or marble

Banded gneiss

Gneiss, typically quartz–feldspar–mica assemblage

Black Tourmaline

Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)4)

Ptygmatic Migmatite

Migmatite (consisting of Neosome and Paleosome fractions)

Gneiss

Gneiss (High-grade metamorphic rock composed primarily of Quartz, Feldspar, and various Micas)

Sodalite

Sodalite (Na8(Al6Si6O24)Cl2)

Weathered limestone or calcareous concretion

Calcite-rich limestone; predominantly calcium carbonate (CaCO₃)

Banded gneiss

Gneiss, typically quartz–feldspar–mica assemblage

Mixed gemstone jewelry collection

Various gemstone minerals, including likely amethyst (quartz), sapphire or iolite, garnet, pearl, turquoise, and colored beryl or tourmaline

Mixed collection of common river stones

Varied lithologies, visibly including quartz-rich rock, dark mafic rock, sandstone, and purple quartz-bearing material

Mixed Mineral Specimens

Mixed Silicates, Oxides, and Phosphates (SiO₂, Ca₅(PO₄)₃(F,Cl,OH), Na₈Al₆Si₆O₂₄Cl₂, etc.)

Quartz-rich metamorphic rock, likely mica schist

Mica schist; chiefly quartz (SiO₂) and mica, likely muscovite/biotite, with possible feldspar

Greenstone or Epidote-rich rock

Epidote or Chlorite schist/greenstone

Dalmation Stone

Peralkaline Rock (mixed silicate minerals)

Mixed small mineral specimens, likely quartz varieties

Uncertain from the image; translucent pieces may be quartz (SiO₂), while golden-brown pieces could be iron-stained quartz or calcite