Economic Importance
Phonolites can be of interest as dimension stone or as aggregate for gravels.
Rarely, economically mineralised phonolite-nepheline syenite alkaline complexes can be associated with rare earth mineralisation, uranium mineralisation and phosphates, such as at Phalaborwa, South Africa.
Phonolite tuff was used as a source of flint for adze heads and such by prehistoric man from Hohentwiel and Hegau, Germany.
Read more about this topic: Phonolite
Famous quotes containing the words economic and/or importance:
“Just as men must give up economic control when their wives share the responsibility for the family’s financial well-being, women must give up exclusive parental control when their husbands assume more responsibility for child care.”
—Augustus Y. Napier (20th century)
“The chimney is to some extent an independent structure, standing on the ground, and rising through the house to the heavens; even after the house is burned it still stands sometimes, and its importance and independence are apparent.”
—Henry David Thoreau (1817–1862)