1. Geophysical Laboratory, Carnegie Institution for Science, 5251 Broad Branch Road NW, Washington, D.C. 20015, U.S.A.
2. Tetherless World Constellation, Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, U.S.A.
3. Department of Mathematics, Computer Science, and Statistics, Purdue University Northwest, Hammond, Indiana 46323, U.S.A.
4. Department of Geosciences, University of Arizona, 1040 East 4th Street, Tucson, Arizona 85721, U.S.A.
5. Department of Geology, Southern Illinois University, Carbondale, Illinois 62901, U.S.A.
6. Http://mindat.org, 128 Mullards Close, Mitcham, Surrey, CR4 4FD, U.K.