Search Mineralpedia – A Mineral Photo Database and Identification Guide
Named after Professor of Crystallography at Geneva University in Geneva, Switzerland, Klaus Yvon. Yvonite is found in only two countries Worldwide, France and the Czech Republic and takes its type locality from the Salsigne mine in France. There, it is formed as a secondary mineral on samples from gold-bearing arsenic sulfide mine dumps.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/yvonite.pdf