Phonolite
“The rock that rings like a bell”
Igneous
Phonolite is a rare volcanic rock with an unusual chemical composition rich in alkali elements. When struck, thin slabs of phonolite produce a clear, resonant tone — a property that has fascinated geologists and musicians alike for centuries.
Composition
nepheline, alkali feldspar, aegirine, titanite, apatite
Where Found
Devils Tower (Wyoming, USA), Cripple Creek (Colorado), East African Rift, Canary Islands, Bohemia
Mohs Hardness
5.5-6
Fun Fact
In the 1840s, a musical instrument called the 'Rock Harmonicon' was built from phonolite slabs quarried in England's Lake District and toured internationally.
Test Your Knowledge
What gives phonolite its ability to ring with a clear tone when struck?
Related Specimens
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