Trip to Hastie Quarry in Hardin County

Brett Denny led a field trip for Dr. John Rakovan of Miami University (Oxford, Ohio) and 17 students to Hastie Quarry in Hardin County, southern Illinois to examine the occurrence and distribution of fluorite deposits in the area. Fluorite, the Illinois state mineral, occurs abundantly in the area and provided a significant portion of the U.S. fluorite production until 1990. There is renewed interest in mining fluorite in southern Illinois and western Kentucky. Fluorite has many uses, including the manufacture of glass and the production of hydrofluoric acid. Flourite is also used as a source of fluorine in toothpastes and in various forms in fluoridation of drinking water.