Igneous

Amethyst (Pale/Light Variety)

Quartz (Silicon Dioxide) with Iron impurities - SiO2

Banded Agate (specifically Black Sardonyx/Onyx variety)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Native Gold (in Jewelry)

Gold (Au)

Moonstone

Orthoclase Feldspar ((K,Na)AlSi3O8)

Smoky Quartz

Smoky Quartz (Silicon Dioxide, SiO2)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Chalcedony (Quartz Var.)

Silicon Dioxide (SiO2)

Quartz with Muscovite Mica

SiO2 with KAl2(AlSi3O10)(OH)2

Labradorite

Labradorite ((Ca, Na)(Al, Si)4O8)

Pyrite

Iron Sulfide (FeS2)

Pyrite

Iron Disulfide (FeS2)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Porphyry (specifically Porphyritic Rhyolite or Andesite)

Porphyritic Igneous Rock (composed of Phenocrysts in an Aphanitic groundmass)

Basalt (Water-worn pebble)

Mafic Igneous Rock (primarily Plagioclase feldspar and Pyroxene)

Granite

Phaneritic Igneous Rock (composed of Quartz, Feldspar, and Mica)

Basalt

Mafic igneous rock (primarily Plagioclase feldspar and Pyroxene)

Pink Granite

Phaneritic plutonic igneous rock (Alkali-feldspar granite)

Vesicular Basalt with Secondary Mineral Inclusions

Aphanitic Mafic Igneous Rock (primarily Plagioclase and Pyroxene)

Basalt River Stone

Aphanitic Mafic Igneous Rock (primarily Plagioclase and Pyroxene)

Basalt (Crushed Roadstone)

Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Basalt

Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)

Granite

Granite (Phaneritic Igneous Rock / Quartz, Feldspar, Mica)

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Basalt with Caliche

Extrusive Mafic Igneous Rock with Secondary Carbonate Crust

Basalt

Mafic Igneous Rock (composed primarily of Plagioclase and Pyroxene)

Pink Granite

Phaneritic intrusive igneous rock (K-feldspar rich)

Granite (Pink/Red Granite)

Phaneritic Igneous Rock (primarily SiO2, KAlSi3O8, NaAlSi3O8)

Pink Granite

Phaneritic Igneous Rock (high K-feldspar content)

Pumice

Vesicular Rhyolite (highly vesicular igneous volcanic rock)

Basalt with Iron Oxidation

Extrusive Mafic Igneous Rock (composed of Plagioclase and Pyroxene)

Granite

Plutonic Igneous Rock (composed of Quartz, Feldspar, and Mica)

Granite with Orthoclase and Hematite Staining

Phaneritic Felsic Igneous Rock (primarily SiO2 with KAlSi3O8)

Feldspathic Granite (likely Syenite or Granite Pegmatite)

Phaneritic Acidic Igneous Rock (KAlSi3O8 dominant with SiO2)

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Granite (specifically Brown Granite Countertop)

Phaneritic Felsic Igneous Rock (Granite-Gabbro series)

Obsidian

Volcanic glass (SiO2-rich extrusive igneous rock)

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Sedimentary or Igneous Matrix

Porphyry

Porphyritic Igneous Rock (likely Porphyritic Andesite or Basalt)

Basalt

Extrusive Igneous Basalt (contains Plagioclase Feldspar and Pyroxene)

Basalt with Pahoehoe flow texture

Vesicular Basalt (Aphanitic Mafic Igneous Rock)