Igneous, Metamorphic, And Sedimentary (Mixed Assemblage)

Pyrite-bearing quartz rock

Pyrite (FeS₂) in quartz-rich matrix, possibly with mica or chlorite

Banded gneiss cobble

Gneiss, typically quartz–feldspar–mica assemblage

Biotite-bearing metamorphic rock, likely schist

Mica schist; quartz–feldspar–biotite assemblage

Mixed rounded river pebbles, likely basalt and granite

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

African Jade

Grossular Garnet in massive rock matrix

Mica-rich schist (likely biotite–muscovite schist)

Mica schist; composed chiefly of muscovite and/or biotite with quartz and feldspar

Amphibolite

Amphibolite, composed mainly of amphibole and plagioclase feldspar

Gneissic granite cobble

Granitic gneiss; quartz–feldspar–biotite assemblage

Eclogite

Eclogite (Omphacite and Pyrope-Almandine Garnet)

Metallic sulfide mineral specimen, likely pyrite

Pyrite (FeS₂), possibly a pyrite-rich sulfide aggregate

Granite (likely)

Coarse-grained felsic intrusive igneous rock, principally quartz and feldspar with dark mica or amphibole

Mixed river gravel (alluvial conglomeratic sediment)

Polymictic alluvium; composition includes quartz, feldspar, chert, granite, basalt, and metamorphic rock fragments

Biotite-bearing mica schist (probable)

Mica schist, chiefly quartz + muscovite/biotite; composition is uncertain from the photograph

Mixed rock fragments, likely granite and weathered metamorphic rock

Granite (quartz–feldspar–mica aggregate) with probable schist/gneiss fragments

Sodalite

Na8Al6Si6O24Cl2

Red Jasper with Quartz Veining

Microcrystalline Quartz (SiO2)

Crushed Stone / Gravel

Aggregate (mixed lithology)

Gravel and Sediment Sample

Mixed clastic sediment

Limestone and Quartz Gravel with Petrified Wood

Sedimentary gravel aggregate and fossilized wood

River Rock

Mixed lithology clast

Epidosite (Epidote-rich rock)

Epidosite (consisting primarily of Epidote: {Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH))

Polished unakite

Unakite; altered granite composed mainly of epidote, pink potassium feldspar, and quartz

Mica-rich schist (probable)

Mica schist, likely muscovite–chlorite schist; exact minerals cannot be confirmed from the image

Mixed tumbled river pebbles and beach stones

Polymictic alluvial gravel; components include quartz, chert, jasper, sandstone, and altered volcanic rocks

Weathered basaltic rock

Basalt, likely altered/vesicular basalt (plagioclase–pyroxene–olivine assemblage)

Mixed Gemstone Collection

SiO2 (Quartz varieties) and Biogenic CaCO3 (Nacre)

Blue Apatite

Fluorapatite (Ca5(PO4)3(F,Cl,OH))

Magnetite

Magnetite (Fe3O4)

Magnetite

Magnetite (Fe3O4)

Magnetite

Iron(II,III) oxide (Fe3O4)

Blue Apatite

Calcium phosphate fluoride, Ca5(PO4)3(F,Cl,OH)

Basalt with Xenolith

Extrusive Igneous Rock containing Mantle Xenolith

Pyrite-bearing sulfide specimen

Pyrite (FeS₂), possibly with chalcopyrite (CuFeS₂) and/or marcasite

Mixed rock specimens; likely breccia and quartz-bearing rocks

Indeterminate from the image; the brown, angular clasts may be breccia, with white quartz or calcite pieces nearby

Graphite

Graphite (Carbon, C)

Banded iron formation fragment

BIF; hematite–magnetite–chert/quartz assemblage

River Pebbles (Mixed Suite)

Mixed lithologies: Quartzite and Gneiss

Weathered granitic rock fragment

Granite, predominantly quartz–feldspar–mica assemblage

Weathered porphyritic volcanic rock (likely basaltic andesite)

Porphyritic basaltic andesite; mineral assemblage likely plagioclase, pyroxene, and iron oxides

Rhodonite

Rhodonite (Mn,Fe,Mg,Ca)SiO3

Lapis Lazuli

Complex silicate rock (lazurite, calcite, pyrite)

Mica-bearing metamorphic rock, likely schist

Muscovite–biotite schist, possibly phyllite