CLASTOUR: a computer program for classification of the minerals of the tourmaline group

Abstract

Tourmaline is the most important borosilicate mineral and a dominant carrier of boron, occurring in different geologic environments. Recently, many investigators have focused on the enhanced understanding of crystal chemistry of this complex mineral group. CLASTOUR is a program package for IBM-compatible personal computers that can be used for classification of the tourmaline group. The program classifies most of the currently valid tourmaline end-members together with other hypothetical end-members. Because it is difficult to establish OH − and O 2− contents at the V- and W-sites without carrying out bond valance sum (BVS) calculations, CLASTOUR gives alternative names for some tourmalines including dominant O 2− anion at their V- and W-sites. The program is developed to edit, to store and to calculate the tourmaline analyses obtained both from electron-microprobe and wet-chemical studies. It is designed to calculate entered tourmaline analyses into cation and molecular percentages, to share cation site-allocations at the different structural positions and to give mole percent of the end-members of alkali-, calcic-, and X-site vacant-group tourmalines. Thus, CLASTOUR makes it possible to plot various types of binary and ternary diagrams under the Grapher software. This program is a user-friendly software with pull-down menus, base-function keys, help menus, extensive error codes and mouse options. The compiled program together with the test data files and graphic files is approximately 1160 kB.