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 idealist’s programme of political or economic reform may be impracticable, absurd, demonstrably ridiculous; but it can never be successfully opposed merely by pointing out that this is the case. A negative opposition cannot be wholly effectual: there must be a competing idealism; something must be offered that is not only less objectionable but more desirable.”
—Charles Horton Cooley (1864–1929)
“We have been told over and over about the importance of bonding to our children. Rarely do we hear about the skill of letting go, or, as one parent said, “that we raise our children to leave us.” Early childhood, as our kids gain skills and eagerly want some distance from us, is a time to build a kind of adult-child balance which permits both of us room.”
—Joan Sheingold Ditzion (20th century)