Because it is an ILLUSION to think that it is possible to understand a rock, an ore, or any other geological material simply by looking at it in a hand sample or even with a magnifying glass or stereomicroscope. At most, it is possible to recognize some common minerals if they are of a reasonable size and well individualized.

Because NO ONE has the vision of an X-ray diffractometer and can identify the minerals in a rock or ore. Especially those of small size. This is mainly true for materials (rocks and ores) with fine grain size and dark colors.

Because microscopy is the FASTEST and CHEAPEST analytical method for identifying minerals and, consequently, for classifying rocks and ores.

Because microscopy is the ONLY way to recognize rock and ore textures. Understanding textures becomes increasingly important as high-grade ores are already exploited and it becomes necessary to work with low-grade ores, where the loss of grade in the tailings becomes unacceptable.

Because the number of different mineral species in rocks and ores is generally GREATLY UNDERESTIMATED. A well-done microscopy can increase the number of different minerals recognized in a given material by 50%.

Because it is UNACCEPTABLE (not to use a stronger term!) to meticulously describe all the transparent minerals in a rock and collectively refer to the opaque minerals simply as “opaque,” without making a section or polished thin section for the identification of these minerals.