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Phonolite identification and geology

Phonolite rock reference specimen

Fine-grained alkaline volcanic rock containing nepheline or leucite. Rings when struck, hence the name Greek: phone = sound . Texture: Aphanitic to porphyritic. Rock type: Igneous Extrusive. Grain size: Fine. Minerals present: Nepheline, Sanidine, Aegirine, Leucite. Formation: Erupts from alkaline volcanic systems in continental rifts and oceanic hotspots. Common geological settings: East African Rift, Canary Islands, Germany Eifel ; the extrusive equivalent of nepheline syenite. Common look-alikes and related entries: Trachyte, Basalt, Tephrite.

Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

Editorial owner
GeoMiner
Last updated
2026-03-30T14:38:11.768738+00:00
Review status
Published; not independently peer-reviewed
  • Rocks — U.S. National Park Service. Authoritative overview of rock groups, the rock cycle, and geologic processes.
  • Can you identify my rock or mineral? — U.S. Geological Survey. Identification limitations and routes to in-person professional verification.

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Common questions

What is Phonolite?
Fine-grained alkaline volcanic rock containing nepheline or leucite. Rings when struck, hence the name Greek: phone = sound .
How can you identify Phonolite?
Compare several properties rather than relying on colour alone. This entry records rock type: Igneous Extrusive; texture: Aphanitic to porphyritic; grain size: Fine; common minerals: Nepheline, Sanidine, Aegirine, Leucite. Confirm an important identification with additional field tests or qualified laboratory work.
How does Phonolite form?
Erupts from alkaline volcanic systems in continental rifts and oceanic hotspots.
Where is Phonolite commonly found?
East African Rift, Canary Islands, Germany Eifel ; the extrusive equivalent of nepheline syenite.
What is Phonolite commonly confused with?
Phonolite may be confused with Trachyte, Basalt, Tephrite. Compare multiple diagnostic properties because colour and surface appearance can overlap.

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