It has been studied in optical mineralogy that the Interference Colors are normally divided into orders such as 1^st, 2^nd, 3^rd, and so on. This actually corresponds to the amount by which the two rays of light are out of phase. The chosen conventional standard is the wavelength of 560 nm. With careful observations made, it can be noticed that some colors repeat themselves on the interference chart so that there is a 2^nd- and 3^rd-order red, for example. These repeated colors become paler with increased order from the color intensity, or by direct comparison with the chart.

            The simplest method in the field of optical mineralogy to determine the order of color is to look at the edge of mineral grains. Grains are normally wedge-shaped at their margins and as the thickness reduces so will the interference color. It is nearly always possible to observe the unique and distinctive 1^st-order white or grey at the edge of a grain that displays color rings when specimen sample is evaluated using a moderate- or high-power objective of petrographic polarizing microscopes used in optical mineralogy. By counting the color rings, the order of color in the main part of the mineral section may be determined. Only when the mineral has an extreme birefringence, and hence a very large number of color rings, will this technique not work.