The CIPW Norm was developed in the early 1900s and named after its creators, the petrologists Charles Cross, Joseph Iddings, Louis Pirsson, and the geochemist Henry Washington.
The CIPW normative mineralogy calculation is based on the typical minerals that may be precipitated from an anhydrous melt at low pressure, and simplifies the typical igneous geochemistry seen in nature with the following four constraints: This is an artificial set of constraints, and therefore the results of the CIPW norm do not reflect the true course of igneous differentiation in nature.
The primary benefit of calculating a CIPW norm is determining what the ideal mineralogy of an aphanitic or porphyritic igneous rock is.
Secondly, the degree of silica saturation of the melt that formed the rock can be assessed in the absence of diagnostic feldspathoid species.
The following areas create the most errors in calculations; For this reason it is not advised to utilise a CIPW norm on kimberlites, lamproites, lamprophyres and some silica-undersaturated igneous rocks.