| Basalt |
Rich in iron and magnesium |
Fine-grained |
Dark black |
Extrusive |
Construction, aggregate |
Iceland, Hawaii |
| Rhyolite |
High silica content |
Fine-grained |
Light color |
Extrusive |
Glass production, jewelry |
Yellowstone, Mount St. Helens |
| Andesite |
Intermediate silica content |
Porphyritic |
Gray to green |
Extrusive |
Construction, decorative rock |
Andes mountains, Japan |
| Obsidian |
Volcanic glass |
Glassy |
Black, green, brown |
Extrusive |
Cutting tools, jewelry |
Various locations |
| Pumice |
Highly vesicular basalt |
Vesicular |
Light gray to cream |
Extrusive |
Abrasive, lightweight concrete |
Mount St. Helens, Lipari Islands |
| Tuff |
Ash and volcanic rock fragments |
Pyroclastic |
Varied colors |
Extrusive |
Building stone, lightweight aggregates |
Italy, Mexico |
| Dacite |
High silica and sodium |
Porphyritic |
Light to dark gray |
Extrusive |
Construction |
Cascade Range |
| Scoria |
Vesicular basalt |
Vesicular |
Reddish to black |
Extrusive |
Drainage, filtration |
New Zealand, Iceland |
| volcanic breccia |
Angular fragments of volcanic materials |
Pyroclastic |
Various colors |
Extrusive |
Construction |
Various locations |
| Volcanic ash |
Fine volcanic fragments |
Ashy |
Gray to white |
Extrusive |
Soil amendment, construction |
Various locations |
| Lapilli |
Small volcanic fragments |
Pyroclastic |
Varied |
Extrusive |
Landscaping, construction |
Various locations |
| Basaltic andesite |
Intermediate composition |
Fine-grained |
Gray to black |
Extrusive |
Construction aggregates |
Various locations |
| Trachyte |
Rich in potassium feldspar |
Porphyritic |
Light-colored |
Extrusive |
Tiles, dimensional stone |
Various locations |
| Vesicular basalt |
Basalt with vesicles |
Vesicular |
Dark gray to black |
Extrusive |
Lightweight construction |
Hawaii, Iceland |
| Volcanic glass |
Lava that cools quickly |
Glassy |
Dark to green |
Extrusive |
Jewelry, tools |
Various locations |
| Tephra |
Fragmented material from volcano |
Pyroclastic |
Various |
Extrusive |
Soil improvement, landscaping |
Various locations |
| Tachylite |
Dark volcanic glass |
Glassy |
Black |
Extrusive |
Insulation, ceramics |
Various locations |
| Calc-alkaline basalt |
Basalt with alkaline properties |
Fine-grained |
Dark |
Extrusive |
Geothermals, construction |
Ring of Fire |
| Hypersthene andesite |
Rich in hypersthene |
Porphyritic |
Gray to green |
Extrusive |
Construction |
Various locations |
| Cinder cone |
Small volcanic structure |
Coarse-grained |
Dark gray to black |
Extrusive |
Landforms |
Various locations |
| Felsic volcanic rock |
Rich in lighter elements |
Fine to coarse |
Light-colored |
Extrusive |
Gemstone alternatives |
Various locations |
| Hawaiian basalt |
Fluid, less viscous |
Fine-grained |
Black to reddish |
Extrusive |
Paving, aggregate |
Hawaii |
| Explosive volcanic rock |
Fragmented from eruptions |
Pyroclastic |
Various colors |
Extrusive |
Erosion control |
Various locations |
| Perlite |
Volcanic rock with water |
Puffed and airy |
White to gray |
Extrusive |
Horticultural use, insulation |
Various locations |
| Rhyolitic pumice |
Rhyolitic lava with bubbles |
Vesicular |
Light gray |
Extrusive |
Lightweight aggregate, landscaping |
Various locations |
| Amorphous volcanic rock |
Non-crystalline structure |
Glassy |
Various colors |
Extrusive |
Decorative use |
Various locations |
| Calc-alkaline magma |
Rich in Ca and Al |
Varied |
Various |
Intrusive/Extrusive |
Mineral resources |
Subduction zones |
| Alkaline basalt |
High in Na and K |
Fine-grained |
Dark |
Extrusive |
Building materials, aggregate |
Various locations |
| Peralkaline rhyolite |
Rich in alkalis |
Fine-grained |
Light color |
Extrusive |
Construction, ceramics |
Various locations |
| Mafic volcanic rock |
Low silica content |
Fine to coarse |
Dark-colored |
Extrusive |
Road base, landscaping |
Various locations |
| Ultramafic rock |
Very low silica content |
Coarse-grained |
Darker shades |
Intrusive/Extrusive |
Mineral extraction |
Varies widely |
| Basaltic lava |
Basalt that erupts |
Mafic |
Black to dark gray |
Extrusive |
Paving, aggregate |
Hawaii, Iceland |
| Felsic lava |
High silica lava |
Viscous |
Light-colored |
Extrusive |
Construction, ceramics |
Various locations |
| Rhyolitic lava |
High in silica |
Thick, viscous |
Light cream to pink |
Extrusive |
Glass, pottery |
Various locations |
| Granitic tuff |
Tuff with granite fragments |
Pyroclastic |
Various colors |
Extrusive |
Building material |
Various locations |
| Tuffaceous sandstone |
Sandstone with tuff |
Sedimentary |
Tan to brown |
Extrusive |
Stonemasonry |
Various locations |
| Spilite |
Altered basalt |
Fine-grained |
Dark green or blue |
Extrusive |
Construction stone |
Various locations |
| Peridotite |
Ultramafic rock |
Coarse-grained |
Green |
Intrusive |
Mineral resources |
Earth's mantle |
| Phonolite |
Contains feldspathoids |
Fine to coarse |
Light gray to green |
Extrusive |
Tile, construction |
Various locations |
| Syenite |
Feldspar-rich |
Coarse-grained |
Light-colored |
Intrusive |
Construction stones |
Various locations |
| Diabase |
Fine-grained gabbro |
Fine-grained |
Dark |
Intrusive |
Road base, gravels |
Various locations |
| Granodiorite |
Intermediate between granite and diorite |
Coarse-grained |
Light gray to black |
Intrusive |
Construction |
Various locations |
| Monzonite |
Equal amounts of quartz and feldspar |
Coarse-grained |
Gray |
Intrusive |
Stone products |
Various locations |
| Pegmatite |
Large crystal size |
Coarse-grained |
Light-colored |
Intrusive |
Gemstones, rare minerals |
Various locations |
| Granite |
Feldspar-rich |
Coarse-grained |
Light-colored |
Intrusive |
Countertops, buildings |
Various locations |
| Gabbro |
Coarse-grained basalt |
Coarse-grained |
Dark |
Intrusive |
Building stone, aggregates |
Various locations |
| Aplite |
Very fine-grained granite |
Fine-grained |
Light-colored |
Intrusive |
Decorative stone |
Various locations |
| Anorthosite |
Rich in plagioclase |
Coarse-grained |
Light to dark gray |
Intrusive |
Crushed rock, countertops |
Various locations |
| Eclogite |
High-pressure metamorphic |
Coarse-grained |
Green |
Intrusive |
Gemstones |
Various locations |
| Scapolite syenite |
Feldspathoidal syenite |
Coarse-grained |
Light to dark gray |
Intrusive |
Construction |
Various locations |
| Vulkanite |
Volcanic rock with different compositions |
Varies |
Varies |
Extrusive/Intrusive |
Decorative stones |
Various locations |
| Québec basalts |
Specific geological region |
Fine-grained |
Dark-colored |
Extrusive |
Construction, aggregate |
Canada |
| Cretaceous volcanic rocks |
Age-based classification |
Varies |
Varies |
Extrusive |
Petroleum exploration |
Various locations |
| Tertiary igneous rocks |
Age-based classification |
Varies |
Varies |
Extrusive |
Mining and resources |
Various locations |
| Flysch |
Sedimentary rock formation |
Layered |
Various colors |
Sedimentary |
Natural barriers |
Various locations |
| Volcanic palagonite |
Altered volcanic glass |
Coarse-grained |
Green to yellow |
Extrusive |
Land reclamation |
Various locations |
| Strombolian eruption rocks |
Type of volcanic eruption |
Coarse- to fine-grained |
Dark to reddish |
Extrusive |
Research and tourism |
Stromboli Island |
| Plinian eruption rocks |
Highly explosive |
Pyroclastic |
Various colors |
Extrusive |
Catastrophic event studies |
Mount Vesuvius |
| Vesicular basaltic tuff |
Tuff with vesicles |
Pyroclastic |
Varied colors |
Extrusive |
Landscaping |
Various locations |
| Subalkaline basalt |
Low in alkali |
Fine-grained |
Dark |
Extrusive |
Construction material |
Various locations |
| Acidic volcanic rock |
High silica content |
Fine to coarse |
Light-colored |
Extrusive |
Ceramics, pottery |
Various locations |
| Composite volcano rocks |
From stratovolcanoes |
Varied |
Varied |
Extrusive |
Geological studies |
Varied locations |
| Stratovolcano tuff |
Tuff from stratovolcanoes |
Pyroclastic |
Varied |
Extrusive |
Engineering |
Various locations |
| Primary volcanic rock |
Formed directly from magma |
Varied |
Varied |
Extrusive |
Research |
Various locations |
| Secondary volcanic rock |
Altered from primary rocks |
Varied |
Varied |
Extrusive |
Geological studies |
Various locations |
| Minor volcanic rock |
Lesser-known types |
Varied |
Varied |
Extrusive/Intrusive |
Research |
Various locations |
| Basaltic lava flow |
Fluid basalt lava |
Varied |
Dark |
Extrusive |
Landscaping, geological studies |
Hawaiian Islands |
| Mid-ocean ridge basalt |
Basalt from underwater |
Fine-grained |
Dark |
Extrusive |
Geological research |
Mid-ocean ridges |
| Volcanic island arc rock |
Formed in island arcs |
Varied |
Varied |
Extrusive |
Tectonic studies |
Japan, Indonesia |
| Flood basalt |
Extensive lava flows |
Coarse-grained |
Dark |
Extrusive |
Mining, resources |
Columbia River Plateau |
| Volcanic sand |
Sand-size volcanic ash |
Varied |
Tan to gray |
Extrusive |
Landscaping, construction |
Various locations |
| Igneous breccia |
Breccia from igneous sources |
Coarse-grained |
Varied |
Intrusive/Extrusive |
Construction |
Various locations |
| Porphyritic volcanic rock |
Contains larger crystals |
Porphyritic |
Dark to light |
Extrusive |
Decorative stones |
Various locations |
| Metamorphic volcanic rock |
Metamorphosed from volcanic rocks |
Varied |
Varied |
Intrusive/Extrusive |
Resource extraction |
Various locations |
| Volcanic diatreme |
Pipe-like vent filled with rocks |
Varied |
Varied |
Extrusive |
Resource mining |
Various locations |
| Graptolitic tuff |
Contains graptolites |
Pyroclastic |
Varied |
Extrusive |
Geological studies |
Various locations |
| Protoliths |
Parent rock for metamorphic conditions |
Varied |
Varied |
Intrusive/Extrusive |
Geological research |
Various locations |
| Volcanic neck |
Solidified lava in vents |
Varied |
Varied |
Extrusive |
Tourism, research |
Various locations |
| Tuff ring |
Circular tuff structure |
Pyroclastic |
Varied |
Extrusive |
Geological studies |
Various locations |
| Volcanic dome |
Mound-shaped structure from thick lava |
Varied |
Varied |
Extrusive |
Tourism, geology |
Various locations |
| Caldera |
Large volcanic crater after an eruption |
Varied |
Varied |
Extrusive |
Tourism, geological research |
Yellowstone, Pinatubo |
| Geothermal rock |
Formed from geothermal activity |
Varied |
Varied |
Extrusive/Intrusive |
Energy production |
Iceland, New Zealand |
| Volcanic plug |
Solidified lava inside a volcano |
Varied |
Varied |
Extrusive |
Geological studies |
Various locations |
| Hot spot volcanic rock |
Formed from hot spot volcanism |
Varied |
Varied |
Extrusive |
Research, energy |
Hawaii, Yellowstone |
| Basalt columnar rock |
Columnar jointing in basalt |
Varied |
Dark |
Extrusive |
Landscaping, tourism |
Giant's Causeway |
| Volcanic pavement |
Flat lava surface |
Varied |
Dark |
Extrusive |
Road construction |
Various locations |
| Inflated lava |
Lava that has expanded |
Vesicular |
Dark |
Extrusive |
Geological studies |
Various locations |
| Volcanic fissure |
Cracks that release lava |
Varied |
Varied |
Extrusive |
Geological studies |
Iceland, East African Rift |
| Plutonic rock |
Formed deep underground |
Varied |
Various colors |
Intrusive |
Granite supply |
Various locations |
| Volcanic activity deposits |
Deposits from eruptions |
Varied |
Varied |
Extrusive |
Land rehabilitation |
Various locations |
| Post-volcanic rock |
After volcanic activity |
Varied |
Varied |
Extrusive/Intrusive |
Resource study |
Various locations |
| Accreted volcanic rock |
Accreted from surrounding areas |
Varied |
Varied |
Extrusive/Intrusive |
Geological studies |
Various locations |
| Volcanic lava tubes |
Channels formed from flowing lava |
Varied |
Dark |
Extrusive |
Tourism, exploration |
Various locations |
| Basalt scoria |
Vesicular basalt with color variations |
Vesicular |
Red to black |
Extrusive |
Landscaping, drainage |
Various locations |
| Volcanic lake deposits |
Deposits in volcanic lakes |
Fine-grained |
Various colors |
Extrusive |
Research, tourism |
Various locations |
| Volcanic gas deposits |
Mineral deposits from gases |
Varied |
Varied |
Extrusive |
Mineral mining |
Various locations |
| Thermal mineral deposits |
Deposits from geothermal activity |
Varied |
Varied |
Intrusive |
Resource extraction |
Various locations |
| Volcanic arc accretion |
Accretion from volcanic arcs |
Varied |
Varied |
Extrusive |
Resource mining |
Various locations |
| Interglacial volcanic rock |
Formed during interglacial periods |
Varied |
Varied |
Extrusive |
Research, sediment studies |
Various locations |
| Vent-proximal facies |
Deposits near a vent |
Varied |
Varied |
Extrusive |
Volcanic studies |
Various locations |
| Post-caldera volcanic rock |
Rock formed after a caldera collapse |
Varied |
Varied |
Extrusive |
Geological research |
Various locations |
| Formation deposits |
Layered volcanic eruptions |
Varied |
Varied |
Extrusive |
Natural resource studies |
Various locations |
| Volcanic sedimentary rocks |
Volcanic material turned sedimentary |
Varied |
Varied |
Sedimentary |
Landscaping and construction |
Various locations |
| Pyroclastic surge deposits |
Rapidly moving gas and ash |
Pyroclastic |
Various colors |
Extrusive |
Research, geology |
Various locations |
| Volcanic debris flow |
Flow of volcanic material |
Coarse-grained |
Varied |
Extrusive |
Landform changes, geology |
Various locations |
| Rhyolite lava dome |
Forms from rhyolitic lava |
Varied |
Light-colored |
Extrusive |
Geology studies |
Various locations |
| Crater lake deposits |
Deposits in craters |
Fine to coarse |
Varied |
Extrusive |
Tourism, geology |
Various locations |
| Isle of Skye basalts |
Specific geothermal area |
Fine to coarse |
Dark |
Extrusive |
Geographic study |
Scotland |
| Chalky volcanic ash |
Ash with high calcareous content |
Fine-grained |
White to light gray |
Extrusive |
Agricultural use |
Various locations |
| Keratophyre |
Felsic volcanic rock |
Fine-grained |
Light to intermediate |
Extrusive |
Mineral resources |
Various locations |
| Volcanic ceramics |
Ceramics made from volcanic materials |
Varied |
Varied |
Extrusive |
Art, construction |
Various locations |
| Subduction zone volcanic rock |
Rock from subduction processes |
Varied |
Varied |
Extrusive |
Resource study |
Ring of Fire |
| Plutonic tuff |
Tuff from deep sources |
Coarse to fine |
Varied |
Extrusive |
Geomorphic studies |
Various locations |
| Volcanic extrusions |
Surface expressions of magma |
Varied |
Varied |
Extrusive |
Geological studies |
Various locations |
| Microcrystalline volcanic rock |
Fine crystals in volcanic rock |
Fine-grained |
Varied |
Extrusive/Intruive |
Research |
Various locations |
| Altered volcanic rock |
Volcanic rock changed by processes |
Varied |
Varied |
Extrusive/Intrusive |
Minerals extraction |
Various locations |