Igneous Rock (Volcanic Glass)

Porphyritic Basalt

Porphyritic Basalt (containing Plagioclase or Alkali Feldspar phenocrysts)

Basalt Pebble

Basalt (Extrusive Mafic Igneous)

Basalt

Basalt (Aphanitic Mafic Igneous Rock)

Basalt

Extrusive Mafic Igneous Rock (composed primarily of plagioclase feldspar and pyroxene)

Jasper

Jasper (Silicon Dioxide, SiO2)

Demitasse Granite (Diorite-Granite transition)

Intermediate Plutonic Rock (Granodiorite/Diorite mix)

Obsidian

Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)

River Quartz (Milky and Smoky mix)

Silicon Dioxide (SiO2)

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite inclusions (SiO2)

Feldspar

Potassium Feldspar (KAlSi3O8)

Granite (Pink/Red)

Phaneritic Igneous Rock (Rich in K-Feldspar)

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Quartz Crystal

Silicon Dioxide (SiO2)

Dyed Agate Geode (Pink/Magenta)

Silicon Dioxide (SiO2) - variety of Chalcedony/Quartz

Cloud Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Basalt with Quartz Vein and Weathering Crust

Amygdaloidal or Porphyritic Basalt

Mahogany Obsidian

Volcanic glass (SiO2 with Hematite or Magnetite inclusions)

Clear/White Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Black Obsidian

Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)

Olivine in Basalt (Peridot)

Magnesium Iron Silicate (Mg,Fe)2SiO4 (Mineral) / Scoriaceous Basalt (Host Rock)

Basalt with Scoria/Vesicular Texture

Vesicular Basalt (Iron-rich/Oxidized)

Mahogany Obsidian

Volcanic Glass with Hematite inclusions (SiO2)

Obsidian

Obsidian (Volcanic Glass, SiO2 dominated)

Basalt

Basalt (comprising Plagioclase feldspar, Pyroxene, and Olivine)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Diabase (also known as Dolerite)

Diabase

Greenstone with Quartz Veining

Epidiorite or Metabasalt with SiO2 (Quartz) veins

Crazy Lace Agate

Chalcedony (Silicon Dioxide, SiO2)

Obsidian

Volcanic glass (mainly SiO2 with inclusions)

Greenstone

Greenschist (metamorphosed mafic igneous rock)

Carnelian Agate Nodule

Silicon Dioxide (SiO2) - Carnelian Chalcedony

Lava Rock (Scoria)

Scoria (highly vesicular basaltic rock)

Dyed Pumice

Vesicular Rhyolite (Artificial Coloration Addition)

Basalt

Basalt (composition predominately Plagioclase feldspar and Pyroxene)

Basalt with Quartz/Epidote Vein

Mafic volcanic rock (formula primarily (Mg, Fe)2SiO4 and CaAl2Si2O8)

Jasper

Silicon dioxide (SiO2)

Carnelian

Carnelian (SiO2, Silicon Dioxide with Iron Oxide impurities)

Basalt

Basalt (primarily composed of Plagioclase feldspar and Pyroxene)

Basalt with Caliche

Extrusive Mafic Igneous Rock with Secondary Carbonate Crust

Diorite (Spotted or Dalmatian Stone pattern)

Diorite

Amygdaloidal Rhyolite (often called Lake Superior Agate relative)

Rhyolite with Calcite/Quartz amygdules (SiO2 and secondary minerals)

Jasper in Rhyolite matrix

Silicon Dioxide (SiO2) with various inclusions in Felsic Igneous matrix