Mineral (Iron Ore)

Pyrite in Shale

Iron Sulfide (FeS2) in Sedimentary Matrix

Yellow Jasper (within host rock)

Silicon Dioxide (SiO2) with iron hydroxides (Goethite)

Scoria (Vesicular Basalt)

Scoria (Extrusive Igneous Rock)

Dendrite (Manganese Oxide Dendrites)

Psilomelane or Pyrolusite on Matrix (typically MnO2)

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic Extrusive volcanic rock)

Honey Calcite

Calcite (Calcium Carbonate, CaCO3)

Yellow Quartz (Citrine-colored Quartz Pebble)

Silicon Dioxide (SiO2)

Amethyst

Amethyst (Silicon Dioxide, SiO2)

Quartz (River Cobble)

Silicon Dioxide (SiO2)

Sandstone (with Iron Oxide staining)

Arenite (primarily SiO2 with Fe2O3 staining)

Moqui Marble (Shaman Stone)

Iron Oxide Concretion (Goethite/Hematite shell with Sandstone core)

Map Jasper (Picasso Stone)

Metamorphosed Calcium Carbonate (Crystalline Limestone or Marble with Silicate inclusions/impurities)

Picture Jasper

Tectonically broken chalcedony (SiO2)

Granite (Weathered)

Course-grained Intrusive Igneous Rock

Picture Jasper

Silicon Dioxide (SiO2) - Opaque Chert/Quartzite variety

Red Siltstone

Siltstone (composed mainly of SiO2 and Fe2O3)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with iron oxide cement)

Epidote in Quartz (Unakite-like specimen)

Epidote (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH)) in Quartz (SiO2)

Moss Agate

Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxide

Jasper

Silicon dioxide (SiO2)

Coarse-grained Quartz with Feldspar inclusions

Crystalline Quartz (SiO2) with Orthoclase/Plagioclase Feldspar inclusions

Serpentinite

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4

Aquamarine

Beryl (Be3Al2Si6O18 with iron impurities)

Aquamarine

Beryl (Be3Al2Si6O18 with iron impurities)

Agate and Amethyst (Quartz variants)

Silicon Dioxide (SiO2) - Microcrystalline Quartz and Crystalline Quartz

Rose Quartz

Silicon Dioxide (SiO2)

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Yellow Quartz (Citrine or Iron-stained Quartz)

Silicon Dioxide (SiO2)

Citrine

Crystalline Quartz (SiO2) with iron impurities

Iron Meteorite

Iron Meteorite (primarily Kamacite and Taenite, Fe-Ni alloys)

Citrine Quartz

Citrine (Silicon Dioxide - SiO2)

Amethyst

Amethyst (Silicon Dioxide - SiO2)

Amygdaloidal Basalt

Basalt with secondary mineral infilling

Sandstone (Picture Sandstone)

Arenite (primarily SiO2 with iron oxide impurities)

Picture Jasper

Silicon Dioxide (SiO2) with impurities

Red Jasper

Silicon Dioxide (SiO2) with Hematite impurities

Porphyritic Basalt (with Quartz or Calcite inclusion)

Porphyritic Basalt (Matrix: SiO2/MgO/FeO, Phenocryst: likely Quartz or Calcite)

Tree Agate

Silicon Dioxide with Chlorite inclusions (SiO2)

Sandstone Concretion

Clastic Sedimentary Concretion (typically Quartz/Silica with Iron Oxide)

Aquamarine

Beryl (Be3Al2Si6O18 with iron traces)

Amethyst

Amethyst (SiO2 with Iron impurities)

Amethyst (Quartz)

Amethyst (SiO2 with iron impurities)