I watched a repeat of an old episode of Expedition Unknown on TV last night, about viking sunstones. They demonstrated this using a clear calcite cleavage rhomb. https://www.discovery.com/shows/expedition-unknown/episodes/viking-sunstone Did anyone else see this, either when the episode first came out, or more recently? Andrea Koziol -- ************************************************************ Dr. Andrea Koziol Dept. of Geology And Environmental Geosciences 300 College Park Dayton OH 45469-2364 akoziol1@udayton.edu Voice: 937-229-2954 *************************************************************