The data is a 53 by 12 matrix representing mineral analysis of a 4500 foot core drilled from a Colorado mountainside. Twelve variables (columns) represent assays of seven mineral contents by one method and repeated assays of five of these by a second method. Fifty-three equally spaced specimens (rows) along the core were assayed. Specimen ID numbers were 200 to 252. H. Chernoff, "The Use of Faces to Represent Points in k-dimensional Space Graphically", Journal of the American Statistical Association, 68, No. 342, 1973, pp. 361-368. Republished by permission of the American Statistical Association.