Igneous, Metamorphic, And Sedimentary (Mixed Assemblage)

Gneiss

Banded gneiss; typically quartz–feldspar–mica assemblage

Gneiss (probable banded metamorphic rock)

Banded gneiss; typically quartz–feldspar–mica assemblage

Magnetite (Lodestone variety)

Magnetite (Fe3O4)

Unakite

Unakite (altered granite)

Unakite

Epidotized Granite

Granite

Granite; chiefly quartz (SiO₂), feldspar, and mica (biotite/muscovite)

Mixed Mineral Collection

Various Silicates and Oxides

Quartz

Silicon Dioxide (SiO2)

Red Granite

Granite

Quartz with Mica inclusions (Pegmatite)

Silicon Dioxide (SiO2) with Muscovite/Biotite inclusions

Jasper and Quartz Breccia

Silica breccia (SiO2)

Tumbled milky quartz

Quartz, SiO₂; trigonal crystal system

Quartz (likely milky or iron-stained quartz)

Quartz, silicon dioxide (SiO₂)

Milky quartz cluster

Quartz (silicon dioxide, SiO₂)

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Milky quartz crystal cluster

Quartz (silicon dioxide, SiO₂)

Weathered quartz-rich pebble

Likely quartz-rich granitoid (quartz and feldspar); exact identification is uncertain from the image

Weathered conglomeratic volcanic rock

Likely basaltic volcanic breccia or agglomerate, with plagioclase, pyroxene, volcanic glass, and lithic fragments

Mixed stone-bead bracelet, likely agate/jasper and possibly sodalite or dyed quartz

Primarily microcrystalline quartz (SiO₂) varieties, with opaque iron-rich chalcedony/jasper and probable blue sodalite or dyed material

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Beach Pebbles and Jasper

Quartz / Microcrystalline Silicon Dioxide (SiO2)

Black Tourmaline

Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)

Blue Apatite

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

Blue Apatite

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

Green Apatite

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

Quartz Crystal

Silicon Dioxide (SiO2)

Weathered granitic rock fragment

Likely granite or granodiorite, composed mainly of quartz, feldspar, and mica

Costume Jewelry Gemstones (Emerald-imitation and semi-precious beads)

BeCuAl6Si6O18 (Beryl structure), frequently simulated by glass or synthetic spinel

Polished blue-gray mineral specimen, likely galena-bearing ore

Galena (PbS), possibly mixed with quartz/calcite and secondary copper minerals

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Citrine Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Gabbro

Mafic intrusive igneous rock

Mixed Pebbles

Polylithic Rock Fragments

Concrete fragment with Aggregate

Anthropogenic Concrete with Calcarious and Siliceous Aggregate

Metallic sulfide mineral specimen, likely pyrite

Pyrite (iron disulfide, FeS₂), possibly mixed with marcasite or chalcopyrite

Faceted Clear Quartz or Diamond Simulant

Silicon Dioxide (SiO2) if Quartz or Cubic Zirconia (ZrO2) if Synthetic