The scientific importance of gem zircon as analytical reference materials

1 Institut fur Mineralogie und Kristallographie, University of Vienna, 1090 Wien, Austria; lutz.nasdala@univie.ac.at 2 Faculty of Gems, Burapha University, Chanthaburi Campus, Chanthaburi, 22170, Thailand 3 Institut fur Geowissenschaften, Johannes Gutenberg-Universitat, 55099 Mainz, Germany 4 Department of Imaging and Applied Physics, Curtin University of Technology, Bentley, 6102, Australia 5 Department of Geosciences, University of Arizona, Tucson, AZ 85721, U.S.A. 6 Department of Mineralogy, Eotvos Lorand University, H-1117 Budapest, Hungary 7 Department of Geoscience, University of Wisconsin, Madison, WI 53706, U.S.A. 8 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, PR China 9 Mincraft Company, Mount Lavinia, Sri Lanka