(Mine St. Sylvestre, Urbeis, Val de Villé, Bas-Rhin, Alsace, France)
Ref.: Dana, E.S. (1892) System of Mineralogy, 6th. Edition, New York. App. 2 (1909), by E.S. Dana and W.E. Ford: 13.
Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 1101.