1Raman Centre for Applied and Interdisciplinary Sciences, 16A Jheel Road, Calcutta 700 075.
2Department of Agricultural Chemistry & Soil Science, University of Calcutta, 35 Ballygunge Circular Road, Calcutta 700 019.
Existing classification or identification methods for clay minerals do not enable us to differentiate between minerals belonging to the same sub-group but differing only in their chemical makeup, such as between different illites. This can be done by grading the minerals by using a procedure derived from fuzzy mathematical application. The grade of a mineral quantifies the compositional differences between minerals of the same type, the extent of its ‘goodness’, the degree of overlap with other types of minerals and the extent of transformation. The process of computation is illustrated here in detail. Grades of 24 minerals belonging to 8 different sub-groups are derived.
