Richard Adolf Zsigmondy (April 1, 1865 - September 23, 1929) was an Austrian-Hungarian chemist. His academic career began at the University of Vienna Medical Faculty, but soon moved on to the Technical University of Vienna and later to the University of Munich in order to study chemistry. In 1897 the Schott Glass factory offered him a job which he accepted. While there he invented the Jenaer Milchglas and conducted some research on the red Ruby glass. Together with the optical instrument manufacturer Zeiss, he developed the slit ultramicroscope. His scientific career continued in 1908 at the University of Gottingen as professor of inorganic chemistry. His most notable research work was in the chemistry of colloids (a certain colored glass) for which he received the Nobel Prize for Chemistry in 1925. In later years he worked on gold hydrosol and used them to characterize protein solutions. While in Jena he developed the slit ultramicroscope. He died in 1929 at the age of 64.