Colloquium: Lincoln Hollister

"The discovery of a natural quasicrystal, the quest to determine how it was formed, and its relevance to processes in the early solar nebula"

Lincoln Hollister

Prof. Emeritus, Department of Geosciences, Princeton University

Summary: Quasicrystals are forms of matter that have symmetries once thought to be forbidden for solids: five-fold symmetry in two dimensions, icosahedral (soccer ball) symmetry in three dimensions. This symmetry was first hypothesized to exist some 30 years ago, and was later found in synthetic compounds.

Five years ago the first (and so far only) natural quasicrystal was discovered at the Mineralogy Museum in Florence. Later, we found that this sample came to earth on a meteorite (a CV3 carbonaceous chondrite) that landed in far eastern Russia. The Russian prospector, who found the original sample while prospecting for platinum and gold in 1979, took us to the site to collect more samples.

The petrologic study of the new samples has uncovered clues as to how an alloy of Al could form naturally, and how the Al and Cu came together at the same place and time.