Mineral Chemistry of Purple and Yellow Fluorite : Insights from High Resolution FTIR Spectroscopy

Abstract

Banded fluorite samples from the Cave-In-Rock Fluorspar District, Illinois offer insights into the evolving hydrothermal fluids that hosted sulfide ore deposition. Earlier studies have shown that fluids responsible for the Cave-In-Rock deposits followed similar trends in crystallization temperature, salinity, and isotope systematics. However, these studies failed to identify chemical and/or environmental factors that correlate with the observed prominent color banding. We present detailed micro-FTIR analyses of hydrous species within a gemmy fluorite specimen from the Hill Mine.