ISO 7404-4:2017规定了一种方法，使用带有20个交叉线交点的分划来确定煤中的微岩石类型、碳矿石和矿石的比例。它仅适用于使用反射白光（约400 nm至700 nm）在抛光颗粒块上进行的测定。特别是在低煤阶煤中，可以使用额外的蓝色、蓝紫色或紫外光激发（365 nm至440 nm）来更好地识别荧光中的脂闪石。

ISO 7404-4:2017 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 (about 400 nm to 700 nm). Additional blue, blue-violet or UV light excitation (365 nm to 440 nm) for better identification of liptinite in fluorescence may be used especially at low rank coals.