French professor of mineralogy Charles-Victor Mauguin (July 19, 1878 – April 25, 1958) was a founder of the International Union of Crystallography (IUCr), and inventor (with Carl Hermann) of an international standard notation for crystallographic groups. Mineralogy is an earth science that involves the chemistry, crystal structure, and physical (including optical) properties of minerals. ... July 19 is the 200th day (201st in leap years) of the year in the Gregorian Calendar, with 165 days remaining. ... 1878 (MDCCCLXXVIII) was a common year starting on Tuesday (see link for calendar). ... April 25 is the 115th day of the year in the Gregorian Calendar (116th in leap years). ... 1958 (MCMLVIII) was a common year starting on Wednesday of the Gregorian calendar. ... German professor of crystallography Carl Hermann (1898 June 17–1961 September 12) was an inventor (with Charles-Victor Mauguin) of an international standard notation for crystallographic groups. ... A crystallographic group is a topologically discrete subgroup of the group of isometries of some geometric space (typically, not necessarily a Euclidean space) with a compact fundamental domain. ...