Basalt

Amethyst

Amethyst (variety of Quartz, SiO2)

Lake Superior Agate

Banded Chalcedony (Silicon Dioxide / SiO2)

Larimar

Blue Pectolite (NaCa2Si3O8(OH))

Greenstone

Metabasalt (Greenstone facies)

Amethyst

SiO2 (Silicon Dioxide) - Purple variety of Quartz

Scoria (Lava Rock)

Mafic extrusive volcanic rock (Scientific formula varies based on mineral content: primarily SiO2, MgO, and FeO)

Chlorastrolite (Isle Royale Greenstone)

Chlorastrolite (Pumpellyite-(Mg,Fe2+): Ca2MgAl2(Si2O7)(SiO4)(OH)2∙H2O)

Montana Moss Agate

Chalcedony (Silicon Dioxide, SiO2)

Chevron Amethyst

Silicon Dioxide (SiO2) with trace Iron (Fe3+)

Lava Rock (Scoria)

Scoria (highly vesicular basaltic rock)

Granite

Phaneritic Plutonic Igneous Rock (primarily composed of quartz, alkali feldspar, and plagioclase)

Chalcedony (Agate/Jasper mix in host rock)

Chalcedony (cryptocrystalline Silicon Dioxide, SiO2)

Scoria (Lava Rock)

Scoria (Extrusive Igneous Rock / Mafic Silicates)

Mahogany Obsidian

Obsidian (volcanic glass with Hematite/Magnetite inclusions)

Sunstone

Heliolite (Aventurine Feldspar, (Ca,Na)((Al,Si)2Si2O8))

Carnelian Agate

Chalcedony (Silicon Dioxide, SiO2) with Iron Oxide impurities

Bauxite

Bauxite (Mixture of Hydrous Aluminum Oxides)

Epidote

Epidote (Ca2(Al,Fe)3(SiO4)3(OH))

Carnelian

Carnelian (variety of Chalcedony, SiO2)

Greenschist

Greenschist (comprising Actinolite, Chlorite, and Epidote)

Agate Geode / Thunderegg

Chalcedony (cryptocrystalline variety of Quartz), SiO2

Magnetite (Iron Ore)

Magnetite (Fe3O4)

Greenschist (Greenstone)

Greenschist

Labradorite

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

Amethyst

Silicon Dioxide (SiO2) with Fe3+ impurities

Granite with Mafic Inclusions

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

Eclogite

Eclogite (comprising Omphacite and Garnet)

Botryoidal Black Chalcedony Geode (Black Grape Agate)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Lake Superior Agate

Silicon Dioxide (SiO2) - Variety Agate

Carnelian

Carnelian (variety of Chalcedony, SiO2)

Larimar (Pectolite)

NaCa2Si3O8(OH)

Ruby

Corundum (Al2O3 with Chromium trace impurities)

Chlorastrolite (Greenstone)

Chlorastrolite (variety of Pumpellyite) - Ca2(Mg,Fe)Al2(SiO4)(Si2O7)(OH)2 · H2O

Greenschist / Migmatite

Regional Metamorphic Complex (Facies: Greenschist to Amphibolite)

Carnelian Agate

Silicon Dioxide (SiO2) - Carnelian variety of Chalcedony

Moss Agate

Chalcedony (Silicon Dioxide with inclusions) - SiO2

Banded Agate

Silicon Dioxide (SiO2) - Chalcedony variety

Yellow Chalcedony (Agate)

Silicon Dioxide (SiO2)

Scoria (Lava Rock)

Scoria (extrusive volcanic rock)

Amethyst

Amethyst (SiO2)

Blue Agate

Chalcedony (SiO2)

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)