BS ISO 7404-4:2025

This document specifies a method, using a graticule with 20 crossline intersections, for determining the proportions of microlithotypes, carbominerite and minerite in coals. It applies only to determinations made on polished particulate blocks using reflected white light. Additional blue, blue-violet or UV light excitation for better identification of liptinite in fluorescence can be used especially for low rank coals.