Man Made (Synthetic Rock)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Basalt Porphyry (River Pebble)

Porphyritic Basalt

Yellow Calcite

Calcium Carbonate (CaCO3)

Milky Quartz

Silicon Dioxide (SiO2)

Bicolor Quartz Pebble

Silicon Dioxide (SiO2) with mineral inclusions

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Chert Nodule (Commonly known as Flint or River Rock)

Silicon Dioxide (SiO2)

Quartz River Pebble

Quartz (Silicon Dioxide, SiO2)

Iron-stained Milky Quartz

Silicon Dioxide (SiO2) with iron oxide inclusions

Ruby in Fuchsite (often confused with Ruby in Zoisite)

Corundum (Al2O3) in Chromium-rich Muscovite (KAl2(AlSi3O10)(OH)2)

Basalt

Basalt (dominated by Plagioclase Feldspar and Pyroxene)

Greenstone (Epidote/Chlorite Rich Rock)

Metabasalt (often contains Epidote Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH))

Quartzite

Quartzite (primarily SiO2)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Granite

Phaneritic Plutonic Felsic Rock (major components: SiO2 and Al2O3)

Unakite

Epidotized Granite

Dendrite (Manganese Oxide Dendrites)

Psilomelane or Pyrolusite on Matrix (typically MnO2)

Granite

Granite (Phaneritic Quartz-Feldspar Rock)

Basalt with Amygdaloidal Inclusions

Aphanitic Mafic Volcanic Rock (Basalt)

Basalt

Basalt (Aphanitic Mafic Igneous Rock)

Amethyst and Ruby in Zoisite

Silicon Dioxide (SiO2) and Anyolite (Zoisite-Hornblende-Ruby mix)

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Sedimentary or Igneous Matrix

Quartzite

Metamorphic Quartz (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Serpentine

Antigorite, Lizardite, or Chrysotile (Mg,Fe)3Si2O5(OH)4

Serpentine (Serpentinite)

Antigorite, Lizardite, and Chrysotile: (Mg,Fe)3Si2O5(OH)4

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

Quartzite

Quartzite (SiO2)

Chert (Field Stone)

Microcrystalline / Cryptocrystalline Quartz (SiO2)

Granodiorite

Granodiorite (Quartz-Feldspar-Biotite Plutonic Rock)

Snowflake Obsidian

Volcanic glass containing Spherulitic Cristobalite (SiO2)

Basalt

Mafic Igneous Rock (composed primarily of Pyroxene and Plagioclase Feldspar)

Desert Rose

Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

Schist

Mica Schist

Ferruginous Quartzite (Iron-stained Quartzite)

Quartzite with Iron oxides (FeO(OH) / Fe2O3)

Schist

Mica Schist

Clear Quartz

Silicon Dioxide (SiO2)

Serpentine

Antigorite / Lizardite / Chrysotile [(Mg,Fe)3Si2O5(OH)4]

Granite

Granite (Phaneritic igneous rock composed of Quartz, Feldspar, and Mica)

Basalt Column Section

Columnar Basalt (Mafic Extrusive Igneous Rock)

Mica Schist

Mica Schist (primarily Muscovite and Biotite composition)

Graphite Schist

C (Carbonaceous Schist)