Bernauer′s Bands (pages 1558–1571)
Dr. Alexander Shtukenberg, Erica Gunn, Dr. Massimo Gazzano, John Freudenthal, Eric Camp, Prof. Ryan Sours, Dr. Elena Rosseeva and Prof. Bart Kahr
Article first published online: 2 MAR 2011 | DOI: 10.1002/cphc.201000963
Twisted crystals: Ferdinand Bernauer proposed in “Gedrillte” Kristalle (1929), that a great number of simple, crystalline substances grow from solution or from the melt as polycrystalline spherulites with helically twisting radii that give rise to concentric optical bands between crossed polarizers (see picture). In fact, rhythmic precipitation and helical twisting often coexist, complicating optical analyses and presenting Bernauer with difficulties in the characterization and classification of the objects of his interest.