Metamorphic (Localized) Or Sedimentary

Clear Quartz

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Yellow Calcite

Calcium Carbonate (CaCO3)

Milky Quartz

Silicon Dioxide (SiO2)

Magnetic Sand Grain / Magnetite Pellet

Magnetite (Fe3O4)

Clear Quartz Crystal

Silicon Dioxide (SiO2)

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

Quartz Crystal Fragment

Silicon Dioxide (SiO2)

Apatite

Fluorapatite (Ca5(PO4)3F)

Note: Image shows a biological specimen (Rat), not a rock. Representative geological equivalent: Galena (due to lead-grey colors in fur).

Galena (PbS)

Quartz (Granular)

Silicon Dioxide (SiO2)

Banded Gneiss

Metamorphic Gneiss

Pink Quartz / Rose Quartz

Silicon Dioxide (SiO2)

Rhodonite

Manganese Silicate (Mn,Fe,Mg,Ca)SiO3

Graphite

Graphite (C)

Gneiss (River Cobble)

Metamorphic Gneiss

Blue Kyanite

Kyanite (Al2SiO5)

Gneiss

Feldspathic biotite gneiss; a high-grade metamorphic rock composed mainly of quartz, feldspar, and mica

Unidentified small rock fragment

Likely quartz-rich material; exact identification is indeterminate from the image

Dark gray rounded river pebble

Likely basalt or fine-grained volcanic rock; exact identification requires testing

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Milky Quartz

Crystalline Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Pyrite-bearing sulfide specimen

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

Red Jasper

Microcrystalline Quartz (SiO2)

Pyrite

Iron Sulfide (FeS2)

Banded gneiss

Orthogneiss or paragneiss, chiefly quartz–feldspar–mica

Banded metamorphic rock, likely gneiss

Biotite–quartz–feldspar gneiss, possibly migmatitic

Metallic sulfide ore, likely pyrite-bearing rock

Pyrite (FeS₂), possibly with chalcopyrite and quartz/host rock

Gneiss

Metamorphic Gneiss

Specular Hematite (Specularite)

Iron(III) oxide (Fe2O3)

Magnetite-rich ironstone (probable magnetite ore)

Magnetite, Fe₃O₄, likely in a fine-grained ironstone matrix

Pyrite

Iron Pyrite (FeS2)

Pyrite (on the right) and Magnetite or Hematite (on the left)

Iron Sulfide (FeS2) and Iron Oxide (Fe3O4 or Fe2O3)

Weathered brown rock, likely sandstone or iron-rich quartzite

Indeterminate; probable quartz-rich sandstone (quartz, feldspar, iron oxides)

Weathered fine-grained stone, likely sandstone or quartzite

Quartz-rich sandstone (possibly weakly metamorphosed quartzite); predominantly SiO₂

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)