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:
“The reality is that zero defects in products plus zero pollution plus zero risk on the job is equivalent to maximum growth of government plus zero economic growth plus runaway inflation.”
—Dixie Lee Ray (b. 1924)
“Think of the importance of Friendship in the education of men.... It will make a man honest; it will make him a hero; it will make him a saint. It is the state of the just dealing with the just, the magnanimous with the magnanimous, the sincere with the sincere, man with man.”
—Henry David Thoreau (1817–1862)