Various methods of detailed observation may be applied, such as the measurement of the size of the elements of the rock by the help of micrometers, their relative proportions by means of a glass plate ruled in small squares, the angles between cleavages or faces seen in section by the use of the rotating graduated stage, and the estimation of the refractive index of the mineral by comparison with those of different mounting media.
Various methods of meticulous observation can be employed, such as measuring the dimensions of rock components using micrometers, comparing their proportions to a grid on a glass plate, examining angles between cleavages or faces observed in section with a rotating stage, and determining the refractive index of the mineral by comparison with different mounting media.