One of the methods of notation devised to express the intercepts of crystal faces on crystallographic axes, proposed by W. H. Miller. The symbols h, k, and l represent whole numbers which are the reciprocals of intercepts along the a, b, and c (or x, y, and z) crystallographic axes respectively. A face which is parallel to a crystallographic axis is indicated by the symbol o. If a crystal face intercepts the negative end of an axis, a bar (negative sign) is placed above the appropriate symbol. A prism will have the general notation of 100 or 110, a pinacoid 001, and a pyramid 101 or 111. When the indices describe a crystal face they are conventionally written without brackets; when they describe crystal form, they are enclosed in brackets.
Subjects: Chemistry — Earth Sciences and Geography.